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A Gentle Introduction to MOSES

1. Table 6 Comparison of Structural Results Page 156 Discussion Automated Files For the automated files install cif install dat big_jack dat and env dat we are going to use the installation files that are in the sample directory They can be found at the following link bentley ultramarine com hdesk runs samples install list htm The use of these files is also found at the following link bentley ultramarine com hdesk runs samples install launch htm bentley ultramarine com hdesk runs samples install transp htm These files are very similar to the tow_auto files in the transportation exercise When you review the general format of the install dat file you will see that it is basically the same as tow_auto dat The main difference is that now we are using a real jacket and therefore more nodes are needed to describe the port_nod and stbd_nod variables The other difference is that we are now using i_connector v_Iway instead of i connector v_can The command i_connector v_lway defines the launchway assembly based on the nodes used with the option port_node and stbd_node This one command certainly saves us much typing The versatility of these files is that you can use them for launch transportation loadout upand and lift You can run all 5 analysis successively or run a subset For our discussion we are going to only run transportation and launch In the cif file we want to leave the value of the launch and tr
2. Figure 53 G Force Statistics for 90 deg Using the Tools Head 90 Unit Wave Height ap 09 Long G Tran G Vert G Roll A Acc F Pitch A Acc Yaw A Acc 36 ex gt on 0 81 32 r 0 72 Long G 10 3 16 2 28 r o 45 0 54 0 63 Boi AAee 0 27 018 4 5 4 68 82 96 11 12 4 13 8 15 2 16 6 18 Period Figure 54 G Force Statistics for 90 deg Using Native Commands After the hydrodynamics results is where our analyses diverged In the native com mands we made a still water load case RAO load cases then we just asked for the default combination of RAOs and environment spectra for the spectral load cases The report ALLOWABLE STRESS MODIFIERS shows the allowable stress mod ifiers for the load cases In the native command method we did not change it so Page 136 the 10 load cases were left with a modifier of 1 00 The corresponding table for the installation tools results is found on page 57 The table shows 24 load cases for the tiedown members with an allowable stress modifier of 1 33 Page 62 shows the loadcases for the dynamic jacket can tiedown system analysis The load case names used in the installation tools is explained in the file docO0001 txt More sorting and combining is done for the installation tools If you open the doc00001 txt file you should be able to find the following explanation of the struc tural load cases For the structural analysis the barge was a
3. Dl 0ut00001 txt C test samples hystat results fs_mom ans GVIM Eee File Edit Tools Syntax Buffers Window Help aSc XaB RRA SSA THA7A MOSES nnn nnn nn February 9 2011 second hai BUOYANCY AND WEIGHT FOR SMIT 5S Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified Results Are Reported In Body System Draft 4 60 Roll Angle 6 66 Pitch Angle 06 800 Wet Radii Of Gyration About CG K X 6 24 K Y 18 87 K 2 19 37 GMT 12 66 GML 153 98 Center of Gravity Sounding Full Name Weight SSSKR sei Jae aoa gune Paar aS ease Part SMITS LOAD_GRO 7706 60 46 08 6 668 4 32 Contents APSS 254 09 5 59 16 29 4 66 6 16 166 66 ASBS 254 09 5 59 16 29 4 66 6 16 166 66 3PSC 747 28 40 00 3 43 2 66 5 21 85 46 3SBC 747 28 46 66 3 43 2 68 5 21 85 46 SPSS 745 06 81 15 10 29 2 68 5 26 85 36 SSBS 745 06 81 15 16 29 2 68 5 20 85 36 Total 11199 48 48 10 6 68 3 85 Buoyancy 11199 47 48 10 0 00 2 34 113 51 10 Figure 5 Results of amp status b_w with type correct ile Edit Tools Syntax Buffers Window Help ABBS OeE aB BARASSA THA74 CAtest samples hystat results fs_mom ans GVIM eo ks Fil February 9 2611 third em m Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified Results Are Reported In Body System Draft 4 60 Roll Angle 6 66 Pitc
4. Figure 12 Compartments Reports for Event 2 This brings us to event 3 The same set of commands are used but with different values Here we are setting the draft for 5 2m Which means that all three valves will be below the water level Here are the results of the checkloc macro KK KK OK k K OK k OK K k ok KK alarm c1 TRUE Ci 5 10 3 2 eK KK OK KK RK ok OK KK ok RK alarm c2 FALSE C2 10 10 2 2 K k k k K K OK KK OK k K k K KK alarm c3 FALSE C3 15 10 0 1999997 Here is the reports in the log files We see that all three compartment have a sounding of 5 2m and each corresponds to an 86 67 full For compartment C1 which is larger the weight of the ballast is also larger Page 25 Bacon Cameo ot TS File Edit Tools Syntax Buffers Window Help QB2EBBS oeE ae BRAISSALPAQl7 0 gt amp status b_w BUOYANCY AND Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified Results Are Reported In Body System Draft 5 26 Roll Angle 6 66 Pitch Angle 6 66 Wet Radii Of Gyration About CG 4 65 K 5 43 K 2 5 15 Center of Gravity Sounding Full Weight X Y Part TEST LOAD_GRO 16 66 Contents 303 67 5 60 151 83 151 83 1207 34 Buoyancy 1066 03 File Edit Tools Syntax Buffers Window Help anpalogci Zal BRR ASAL TRE a COMPARTMENT PROPERTIES Results fre Reported In Body System Process is DEFAULT Units Are Degree
5. amp set launch false amp set transportation true amp set loadout false amp set upend false amp set lift false The other section of i_stab cif that we want to familiarize ourselves with is com Page 30 mented with the word transportation The section has an if statement so that the transportation calculations are only performed if the transportation variable is set to true as we have done here This three line section is what we want to pay attention to for our transportation stability analysis inst_tran wind 83 19 50 100 100 draft 6 trim 0 53 damage 1s 2s 3s 4s 5s no_seakeep The analysis done here uses some defaults The barge is set in a condition where the draft is 6 ft and the trim is 0 53 deg A phantom weight is added so that the system barge plus cargo is at an equilibrium then the stability analysis is performed The only check is that the area ratio be greater than 1 4 and that the range is greater than 36 degrees The stability analysis is done six times one for the intact and once for every damaged compartment listed after the option damage The numbers after wind specify the wind speed in knots for the different analyses intact stability damage stability vortex shedding and structural analysis For our exercise we will use 83 19 knots for intact stability and 50 knots for damage stability for now that covers all of our interests for the CIF f
6. sign is an option This is the exception The PORT_NOD and STBD_NOD options are needed Page 31 These options tell MOSES to use nodes as listed It is important that the node order be from the stern to the bow Or if we were to model a jacket for launch the node order to be from leading to trailing The last setting tells MOSES to place the box model on top of launchways This will cause some assumptions to be made later since we are not telling MOSES sufficient information to make a good model of the launchways For now that is all we are going to discuss of the automated installation macros Please read the sections in the manual that pertain to the sections discussed here We will now be reviewing the log file In this case the log file tells you a bit more about what is going on It tells you that some dimensions were needed but since they were not provided MOSES made an estimate It tells you the weight center of gravity and radii of gyration of the model box The section below the inst_tran command tells us the results of the intact stability analysis We know from the log file that the analysis failed the range criteria and it lets us know that the ballast needed cannot fit in the barge E log00001 txt CAultra hdesk runs samples hystat i_stab ans cum Grima File Edit Tools Syntax Buffers Window Help aule Lal aR SSA Taa 7A Finished Defining Box Using Estimated DEPSKD Dimension Using
7. lt N DIST _ XAxs TILTBEAM GEOMETRY FIGURE 24 Figure 59 Tiltbeam Geometry The following table presents the legs in the various forms they will be labeled and associated Keep this table in mind when we are discussing the assembly Iway com mand Label Leg A Leg B Barge side starboard port Leading node J1003 J1006 Trailing node J0001 J0004 Assembly list first last Table 5 Leg Name shows various labels We are going to discuss the needed data as it appears in the assembly lleg command Near the top of the manual page there is a top view of the launch barge assembly From this sketch you can see the map between the order of the nodes on the command and the location on the barge assembly Also as part of the description we find that Here xJ 1 xJ n are the node names of the nodes along the launch cradle of the jacket in order where J 1 is the first node which will enter the water and J n is the last node which will enter the water This refers back to the leading edge and trailing edge The rest of the paragraphs helps fill out more of the command The launch cradle is considered part of the jacket that rests on the barge skidway BODY_NAME 1 is the body name assigned to the barge where the tiltpins are attached and XB YB and ZB are the coordinates in the BODY_NAME 1 body system of the begining of the skidway on the BODY_NAME 1 Here the skidway should be cons
8. For this analysis a good part of the work is done in perparation as part of the data file Let s start by reviewing the DAT file Here we use a very shoe box looking barge The section that defines the barge is the following amp describe body test pgen test perm 1 plane 0 20 rect 0 6 10 end_pgen The commane amp describe body test creates a body part compartment and piece with the name of test MOSES automatically creates an association to the part compartment and piece for every body For now we are happy to know that there is a body with the name given and that an association with the part compartment and piece has been made The command pgen is short for piece generator The command amp describe piece test could have also been used before the pgen command It is not necessary to have the amp describe piece followed by the pgen command The pgen command and the end_pgen will be sufficient The option perm 1 tells MOSES it is an outer shell therefore it should be included in any displacement calculations The number following perm is used as a multiplier for the calculated displacement In this case MOSES is to multiply the calculated displacement by 1 This is the first time we will be defining compartments with flood and vent valves The points that will be used to locate the valves are part of the body The naming of the points that will be used to locate the valves is part of the body description Here
9. 2 What is the Y radii of gyration K Y CBRG180 3 Why are there only ten rows in the RIGHTING ARM RESULTS report Change the top of the file to read amp dimen DIMEN FEET KIPS amp device oecho no If you look up the command amp device in the user s manual you will see that this option controls part of the output 4 What is different between this output and the original output Page 8 Wceomp Questions 1 What is the maximum amount of ballast for compartment 4C 2 What compartments are filled to 100 3 What is the area ratio at 12 5 degrees Exercise Add the following lines to wcomp dat amp describe body cbrg180 amp describe part cargo pgen cargo cs_curr 1 1 1 cs win 1 1 1 plane 50 70 100 130 rect 14 40 20 end In the hydrostatic section of wcomp cif alter so that it reads HSTATICS kk AAA 3K 3K 3K K K K K K aK CCI I I I I I 3K K K K 2k K K K K stability trans RARM 2 5 10 WIND 100 REPORT END tank_capacity 5p 1 report end end Questions 1 What is the free surface moment for compartment 5P 2 What is the area ratio at 12 5 degrees Page 9 2 3 Free Surface Correction Topics e Tank ballast reporting e Compartment ballasting options Reference files ultra hdesk runs samples hystat fsmom cif fs mom dat Discussion Let s start by reviewing the DAT file Here we use the one of the barges from the barge library SMIT5 There have been three weights added to the barge Th
10. for the beam number The beams are going to be labeled by number from 1 to 80 Notice that the first time through the loop kkk 0 But a beam does not get created until lll is greater than 1 This is done via an if statment amp if Ill gt 1 amp then So the first time through the loop Page 45 the only thing that really gets done is kkk 0 xl 0 name n00 last n00 in short a node name n00 is created The second time through the loop kkk 1 xl 5 name n01 beam n01 bardum n00 n01 last n0l This similar pattern is repeated 10 more times until lll is greater than 11 When Ill 12 kkk 11 xl 55 name n11 beam nll bardum n10 n11 elat n11 16070 0 0 0 0 cat elat last nll This similar pattern is repeated while Ill lt 72 Once lll 72 then the elat definition is taken out Once Ill reaches 80 the loop finishes The last command remembers the units that were in place at the start of the file Figure 22 shows the structural model of the barge In the structural model each element was defined with an element attribute command elat What we are defining here is the weight per foot of each element This complements the amp default nuse command we mentioned earlier Because the barge will get the buoyancy force from the panel model generated with the definition using pgen we do not want the structural elements to also contribute to buoyancy Page 46 The manual page fo
11. 1 2 Basic Stability Exercise 2 0 a 162 1 3 Free Surface Correction Exercise 2 02 162 7 4 Compartment Ballasting Exercise 162 7 5 Stability Check and KG Allow 162 7 6 Review Working with Compartments 162 T Dynamic Flooding ee aye SO Mee a 163 7 8 Basic Frequency Domain lt 3 2 62 i 4 ho e4 Ree bY 163 7 9 Modeling Cargo Exercise 22 2253 oF See eee a eS 164 7 10 Translating from SACS Exercise 00 4 164 7 11 Longitudinal Strength Exercise ooa aa aa 165 7 12 Modeling a Fender oaoa aaa 165 7 13 Tripod Jacket Transportation 4 4 4446 a 165 Page i 1 Introduction The purpose of this document is to provide a gentle introduction to the MOSES software package It is intended as a complement to the MOSES manual example and test files and the web page The approach taken here is to e discuss an example or a test e ask the user to change a few entries and e discuss the changes in the results All of the files needed to complete the exercises are contained in the standard MOSES distribution It is a good habit to copy these files to a working directory so that you can always revert to the original It is up to you to decide to copy the files or work within the ultra directory There is a word of caution to be said here When you receive a MOSES update or you decide to download a new MOSES version the installation wizard wil
12. 3 30 10 Exercise 1 Trans 170 ftt Long 227 ft 2 Area ratio 5 31 Free Surface Correction Exercise 0 31 m Compartment Ballasting Exercise 1 The answers do not change The area of the valve is not important in a static analysis Stability Check and KG Allow Passes Passes For Draft 6 Allowable KG is 14 13 Area Ratio Yaw 0 damage none Con trols Review Working with Compartments 1 Passes Page 162 2 Passes 3 2644 61 Kips 4 4 17 feet 5 5s Op 6 5s 5p and 5c T 3c 7 7 Dynamic Flooding Exercise A 1 9 RY TBRG 2 x axis Event 3 left axis Z TBRG 4 right axis RY TBRG 5 plot 1 4 rax 3 no Exercise B 1 Simulation Terminated Due to Capsizing has changed to Simulation Terminated at Specified Time 2 out0001 column Intern Fl Head and Vlv Diff Head is blank for the one with total time 1200 sec column Intern Fl Head and Vlv Diff Head is full for the one with total time 200 sec Exercise C The command line before tdom should now read 1 amp compartment correct two percent two 0 dynam two 7 8 Basic Frequency Domain Exercise B 1 Yes the righting arm and wind arm have changed Before the changes the righting arm crossed zero the second time after 67 degrees After the change the second zero crossing is around 54 deg 2 Yes the draft and pitch changed The draft is now deeper and the pitch is less Page 163 7 9 Modeling Cargo Exercise Exercis
13. fender Assume the fender is 2 05 meters in diameter and B 2 is 27 3 so the location of the fender point will be 27 3 2 05 29 35 For demonstration I m making a simple assumption that the tanker is wall sided This may not be true This is a good time to point out that the power of MOSES is in its ability to be programmed Part of the burden of programming is leaving enough documentation so that other people or even yourself after a few months can easily return to the command file and use it with minimal effort We do need to address syntax here In MOSES the comment character is MOSES will ignore all of the characters in the command after it reads the character Please be aware that some commands can be structured so that they occupy several lines of text but when you view them in terms of a command item the lines are a con tinuation of the command For example the amp instate command we used earlier to define the location of both bodies occupies two lines A comment after the would tell MOSES to ignore the location option for the barge The note is telling us that the fender attachment point on the body tanker is located at y 29 35 or 29 35m on the starboard side This locates them at y 29 35 in the global coordinate system These are all of the points that begin with the five characters fent In the next section we find the attachment points on the barge These are all of the points that begin with
14. the output contained an echo of all that was read in with inmodel This top section in the output can get rather large In general Page 56 oecho should be set to no The only time I set it to yes is if I am debugging You should be familiar with the last two lines These three lines are all that is needed to convert the SACS model to MOSES format When you run MOSES the new MOSES model will be in sac_tpg ans mod00001 txt This is if you did not change your defaults This completes the converting part of the process In order to check that the conversion was done properly we need to look at the ck_sac cif and ck_sac dat file The check files are the minimal checks Depending on the complexity of the model or what its intended use is other checks may be necessary This exercise presents the minimal checks If you review the DAT file you will see that the first line is needed so that MOSES knows it is a body These checks are done with the intent of using the models in the installation macros Since the installation macros add the amp describe xxx line to the model I do not take the time here to add this line to the mod00001 txt file In general I do not change the mod00001 txt file If you need to convert a file it would be a good idea to copy these four files to your working directory and then just change the SACS part Discussion the short way Now take a look at cnv_ck cif This file is used to convert the SACS model f
15. 100 tells MOSES to increase the horizontal distance from the vessel to the anchor and stop when the tension at the fairlead is 100 kips There are other entities which MOSES can use to stop the change Please see the amp connector manual page Sample of Multi Point Mooring o i i Figure 37 Mooring system before anchor location Notice here that the length of the line 4000 ft is not going to change The next command amp type is very handy Basically this command is to leave oneself messages in the log file In the days of slow computers one would be sitting at the computer wondering if any calculations were happening If we were to stare at the screen wondering if the computer was working for us this message would let us know that it is This is a very basic use Later we will be asking MOSES to give us more meaningful information about our analysis As you may have noticed we try to make the CIF files a bit easier to read by leaving ourselves messages The first message was SET BASIC PARAMETERS and now we have progressed to Mooring Tables We usually set these messages with a row of s In this section we are going to produce the characteristics of both the mooring system and a single catenary mooring line The other thing you may have noticed is that we change the left hand margin depending if we are inside a menu This is not required Page 86 it just makes it easier to read The fir
16. 2 26 6 618 HC3 F_UALUE 15 66 16 66 5 66 6 66 1 66 6 66 2 20 6 618 U3 U_UALUE 15 00 16 66 26 66 6 66 0 00 1 66 2 28 6 618 X Figure 11 Compartments Reports for Event 2 We see changes in the buoyancy and weight report and in the compartment properties report The weight and the sounding of the ballast is included in both reports In the compartment properties report the value for fill type ballast maximum and full maximum has changed Remember this is establishing the artificial limit set with the macro Here again is the quote from the reference manual The change of fluid in the compartmnet occurs statically and can be observed using amp status compartment The maximum volume of fluid in the compartment is artificailly limited by that specified using the add ballast options The values in the Hole Data report do not change This report is in the body system We did not expect a change becuase we changed the location of the body with reference to the global not the body The locations of the valves are not changing nor are the areas or the friction factors The last thing we do as part of this event is make a picture This picture shows that the mean water level is above valve V1 assoicated with point xC1 With the valve open and the water level above the valve location the water level is the same inside and outside the compartment Page 24 Draft 2 2 m Event 2 0 C3 C2 C1
17. 4 3 0 0 90 Change the attachements for the tanker body to the following locations fent1 161 29 35 21 95 fent2 166 29 35 21 95 fent3 176 29 35 21 95 fent4 181 29 35 21 95 Change the attachment for the barge body to the following locations fenbl 0 10 4 3 fenb2 0 5 4 3 fenb3 0 5 4 3 fenb4 00 10 4 3 Change the attachment point order and change the euler angle for the connectors connector f1 fend fenb1 fent1 euler 0 0 180 connector f2 fend fenb2 fent2 euler 0 0 180 connector f3 fend fenb3 fent3 euler 0 0 180 connector f4 fend fenb4 fent4 euler 0 0 180 7 13 Tripod Jacket Transportation Exercise B Page 165 Joint JW110 is where the leg changes outer diameter Page 166
18. 6 8 4 5 7 4 2 6 616 1 6 6 1 6 005 f 9 547 186 66 9 55 86 08 16 6 0 8 16 6 6 5 5 0 6 619 1 6 8 1 6 665 16 168 186 66 198 11 8 08 11 6 6 8 11 6 7 3 5 8 6 621 1 6 6 1 6 605 16 676 186 66 10 67 6 00 13 3 8 0 13 3 8 2 6 6 6 623 1 6 6 1 6 605 H 11 231 186 66 11 23 8 08 16 4 6 6 16 4 9 8 8 3 6 628 1 6 8 1 0 004 H 11 793 186 66 11 79 8 08 19 6 6 8 19 6 11 5 16 8 6 633 1 5 6 8 6 604 I 12 355 180 00 12 35 8 00 24 6 6 6 24 6 14 1 12 6 6 646 1 5 6 6 6 064 12 916 186 66 12 92 0 00 30 8 6 6 30 8 17 3 15 8 6 656 1 5 6 6 6 064 13 478 186 66 13 48 8 08 46 6 6 8 46 6 22 2 26 7 6 663 1 5 6 6 6 604 14 839 186 66 14 04 86 08 54 4 6 6 54 4 29 9 28 4 6 685 1 5 6 8 6 004 i 14 601 180 00 14 60 06 00 77 1 6 6 77 1 42 0 40 5 6 126 1 5 6 6 6 064 ly 15 162 186 66 15 16 8 08 115 9 6 8 115 9 62 8 61 3 6 179 1 5 6 8 6 604 15 724 186 66 15 72 86 08 185 7 6 8 185 7 106 2 98 7 6 286 1 5 6 6 6 604 f 16 286 180 00 16 29 06 00 328 8 6 6 328 8 177 1 175 5 0 506 1 5 6 6 6 064 bs a J Figure 42 Force Report After the connector design menu the hydrodynamic database is calculated For many of our mooring and flexible connector samples this is the standard approach First make some checks on the connector system then continue with the hydrodynamics The hydrodynamic database is calculated in the Hydrodynamics menu Please note that the hydrodynamics of the tanker are the only ones calculated The body buoy is modeled as a tubular which means that on
19. 8 second period These results are in the out file in the report titled CONNECTOR FORCE STATISTICS We want to review the statistics of the forces because the wave properties will change during any operation It is best to get the reactions to a set of expected waves This also helps us check if there are concerns with a change in the frequency of the waves during the operation Reviewing the manual you will find that there are several commands that start with fr_ and st The fr_ indicates the frequency response will be calculated The st indicates the statistics that are based on the frequency response will be calculated This concludes the frequency domain section of the command file Next we will look at a time domain analysis Sidelift Command File Discussion Dynamic Time Domain Analysis In the frequency domain analysis we could define the wave spectrum as part of the statistics command For the time domain analysis we must define the environment with the amp env command The format used is the same in amp env and the option st_cforce sea We see that the spectrum with an 8 second mean period wave is what will be used in the time domain analysis The option time 100 0 2 tells MOSES that the time domain analysis will look at 100 seconds at 0 2 second intervals The time interval chosen here is usually considered rather large but since this analysis is just an example these values will not take long to compute The time
20. Exercise E 1 Copy the testb dat file to testf dat 2 Copy the testb cif file to testf cif 3 Change the weight commands to read as follows beg 200 0 30 weight beg 20589 32 129 129 ldist 0 400 2 Change the cargo weight commands to read as follows cen 0 0 0 weight cen 5000 ldist 5 5 Compare these results to the original results from p_m cif What is the distribution from the amp weight command Page 42 2 7 Longitudinal Strength Part 2 Topics e Flexible barge modeling e Longitudinal strength calculations in the structural analysis menu Reference files long str cif long_str dat Discussion This set of files serve as the introduction to structural analysis We will be comparing the results of the bending moment and shear calculations from traditional naval architecture to the results from the structural analysis method In the structural analysis method the barge is modeled as one long beam The reference files are in the samples directory under the how_to directory The reader should be familiar enough with the web page at this point to be able to locate these files and place them in the directory in which they will be working The top part of the dat file should be familiar This is the section that stores the incoming units and defines the outer shell of the barge It begins with amp describe body barge and ends with end pgen For this barge the bending moment and shear will be calculated at each station listed
21. Page 153 WHERE THE SUPPORT NODES ARE ALL NODES B1 0 ALL NODES 0 L 2 NODE WITH MIN X gt 0 NODE WITH MAX X lt 0 JACKET SUPPORT CONDITION FOR LAUNCH BEFORE TIPPING FIGURE 28 Figure 63 Jacket Support Condition Before Tip The manual tells us that If either SSOLVE NONLINEAR or BODSOLVE is used for solving a launch MOSES will create connections modeling the launchway at each load case The type of restraint supplied in the area of the tiltbeam is dependent on the use of the BEAM option of the LLEG command This option defines the bending stiffness and length of the beam Before tipping all jacket nodes between the two ends of the tiltbeam will be restrained In cases where this criteria does not yield at least two nodes the node furthest forward yet aft of the pin and the node furthest aft yet forward of the pin will be added to the others The selected nodes are then connected with compression only springs to the closest barge nodes For the nodes in contact with the barge proper a nominal stiff spring is used For those in contact with the tiltbeam the stiff spring is put in series with the bending stiffness of the tiltbeam at the proper location The load distribution represented by the use of LCASE in this manner is shown in Figure 63 Jacket Support Condition Before Tip and Figure 43 Jacket Support Page 154 Condition After Tipping SEI Ko Barge Node ec J e Str
22. Radii Of Gyration About CG K X 4 95 K 5 26 K 2 4 92 Name Weight e o Yor oo gase a a Part TEST LOAD_GRO 666 66 16 66 6 66 6 66 Contents Total 728 38 9 12 6 66 5 14 Buoyancy 451 63 16 66 8 08 1 16 hur Figure 10 Buoyancy and Weight Report for Event 2 Page 23 r eee GF 10q00001 txt C test open valve static_open ans GVIM nn File Edit Tools Syntax Buffers Window Help aulae alaaa SA Taal Ra gt amp status compartment a COMPARTMENT PROPERTIES i Results Are Reported In Body System Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified Fill Specific Ballast Full Sounding Name Type Gravity Maximum Current Max Min Curr C1 U_OPEN 1 6256 3560 6 128 4 166 66 6 66 36 67 2 200 c2 CORRECT 1 6256 175 3 6 8 6 66 6 66 6 66 6 666 c3 CORRECT 1 62506 175 3 6 6 6 66 6 66 6 66 6 660 gt amp status v_hole HOLE DAT A Results Are Reported In Body System Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified Hole Location Normal Friction frea Name Type X Y 2 x Y 2 Factor HC1 F_UALUE 5 66 16 66 2 66 6 66 1 66 6 66 2 26 6 618 i v1 U_UALUE 5 66 16 66 26 66 6 66 6 66 1 66 2 20 6 618 HC2 F_UALUE 16 66 16 66 3 66 6 66 1 66 6 66 2 26 6 618 u2 U_UALUE 16 66 16 66 26 66 6 66 6 66 1 66
23. This is why after the open_valve option we find the percent option the percent option is telling MOSES the maximum volume limit of fluid in the compartment This sequence of commands is done for each of the valves The last command amp end Page 19 macro tells MOSES the macro definition has ended The data file ends Discussion Command File The command file begins as many of the other files have It sets the units for the analysis amp dimen dimen meters m tons This file shows how to define the specific gravity of water with amp default spgwater 1 025 Then we tell MOSES we do not care to see an echo of the input model as part of the output file And finally we use the command inmodel to read in the model The command file is set up in sections Each section is assigned an event number with the command amp event_store After the inmodel the event number is 1 We use the macro checkloc to check that location of the valves and the value of the sensors The following is what you should see in the log file as a result of the macro checkloc KK KK OK KK OK OK OK KK ok EK alarm ci FALSE Ci 5 10 2 eK KKK OK KK OK OK OK KK ok ORK alarm c2 FALSE C2 10 10 3 KK KK KK KK ok OK KEKEE alarm c3 FALSE C3 15 10 5 We see that this is the location defined in the data file This makes sense since after the inmodel the body coordinate system origin is at the global coordinate system origin The next three com
24. Top view of configuration with global X and Y axes Having those three views we finish the static analysis portion of the command file Sidelift Command File Discussion Dynamic Frequency Domain Analysis The dynamic analysis portion of the command file begins with the command hydro dynamics This command enters the Hydrodynamics Menu where the hydrodynamic database will be computed The database is a description of the panel pressures below the water surface To generate the pressure database we issue the command g_pressure There are many options that can be used with g_pressure but we are using the bare minimum to complete a dynamic analysis We specify one environment heading and a very small number of periods If this were a real world project both of these lists would be longer and the periods would not be evenly spread Instead they would have a concentration around the peak period with an overall spread to cover the energy of the expected wave spectrum Page 109 In the log file after the g_pressure command we see a very short report of what MOSES is doing We see that strip theory was used to make the calculations and that only 90 panels were used Depending on the shape and size of the vessel we might be interested in 3d diffraction and increasing the number of panels Since this is an exercise we are not going to do a study to determine the best number of panels and the best hydrodynamic theory for our problem Now that we have
25. Type x Y Z x Y 2 Factor m HC1 F_UALUE 5 66 16 66 2 66 6 66 1 66 6 68 2 20 6 618 v1 U_UVALUE 5 66 16 66 26 66 6 66 6 88 1 66 2 26 6 618 HC2 F_UALUE 10 66 16 66 3 66 6 66 1 00 6 66 2 26 6 618 u2 U_UALUE 10 66 16 66 26 668 6 66 6 66 1 88 2 26 6 618 F_UALUE 15 66 10 66 5 60 6 66 1 66 6 66 2 26 6 618 Sd Figure 16 Compartments Reports for Event 4 Please notice that for the fill type in the compartment properties report the valve is still open We did not close the valve we just relocated the body so that the valve would be above the water line Here is the picture showing the water level and the location of the valves Page 28 Draft 2 2 Event 2 o3 C3 C2 C1 Figure 17 Compartments Reports for Event 2 This concludes the exercise on opening valves in a static analysis Questions During the data discussion I mentioned that the area of the valve is not needed for this analysis Comment out the valve areas and see if the results change Page 29 2 5 Stability Check and KG Allow Topics e Introduction to Automated Installation Tools e Working with the stability macros e Familiarization with the amp status command Reference files m_stab cif m_stab dat i_stab cif istab dat box dat Discussion The discussion for i stab cif and i stab dat are located at http bentley ultramarine com hdesk runs samples hystat i stab htm http bentley ul
26. a hydrodynamic database we exit the hydrodynamic menu us ing end We can compute motions and forces First we will perform a frequency domain analysis This is also known as a linear analysis All of the frequency do main analysis is done within the Frequency Response Menu which is entered with the freq_response command After we are finished with the frequency analysis we will exit the Frequency Response Menu with the command end You have to be careful about using the command end This command is used to exit many of the menus Within the Frequency Response Menu we will enter the Disposition Menu We need to make sure we keep track of the use of end so that we do not accidentally exit into a menu and then have to re enter the one just exited Within the Frequency Response Menu the FIRST thing we do is calculate the response amplitude operators This is simply done with the command RAO This command computes the RAO but does not report them MOSES will compute the RAOs at the body origin Once the RAOs are computed for each body we have to tell MOSES which body we are interested in before we ask for the report of the motion RAO This is why there is an amp describe body bname before each of the fr_point commands The log file shows that for each body the RAOs were reported at the local x 0 y 0 and z 0 location the body origin Since these are the default values we are just showing the command order to report the different RAOs
27. after plane This is because the location was not used The section option is needed so that the section modulous and IE can be used in calculations For a review of the options used for a classical naval architecture bending moment and shear calculations please see the following link http bentley ultramarine com hdesk ref_man bod_par htm amp DESCRIBE BODY Figure 21 shows the panel model created at the conclusion of the pgen command The next section we will describe the structural portion of the model This begins on line 36 also with amp describe body barge The command on line 37 reads amp default nuse The is the wild character in MOSES This is the first time we see this command The option is nuse and the other common one is use These are used to turn on use or not use turn off nuse the attributes The attributes are weight dead wind wind added mass amass drag drag and buoyancy buoy Using the sign means we are turning Page 43 them all off The reference for the attributes is at the following link http bentley ultramarine com hdesk ref_man bod_par htm amp DESCRIBE BODY J A EEE A Ye fy ELLE LL LLL EL ELL LEE LLL LLL ELLE LLL LLL LLL LLL LLL LLL ff AITITA III IAIN Figure 21 Iso view of panel model Here we will be defining a class with the character Similar to the character described earlier the is a special character in MOSES T
28. are at the top and bottom of each leg We will also need the ck_sac cif file to determine the order of the nodes This is a very basic jacket The leg with nodes J0006 J0004 we will call LEGA the leg with nodes J0003 and JO001 we will call LEGB Further lets disignate nodes JO006 and J0003 as the top of the jacket This end of the jacket is the leading edge Meaning it leads into the water Nodes J0004 and J0001 are the trailing edge Meaning they go into the water last Now back to the command file The first part of the command file should be familiar to us The new part is in the model editing portion You are familiar with the command medit from previous exercises This is the first time we will be defining a launchway assembly The Page 146 following is the link to the manual page for the command assembly LLEG bentley ultramarine com hdesk ref_man conn_lway htm For this command it would be beneficial if you took the time to read the entire page before starting to look at the specifics of the format There is a figure at the top of the page that is also shown here Figure 58 Yj Launch Direction Xj PLANE VIEW SHOWING JOINTS USED ON LLEG COMMAND FIGUIRF 2A Figure 58 Joints used in the Assembly LLEG command There is a second figure showing the tiltbeam geometry towards the bottom of the page and is shown here as Figure 59 Tiltbeam Geometry Page 147 XB YB ZB TPRIDEP
29. are interested in is envdat on line 51 This is the variable that tells MOSES where the environment duration for fatigue is located We want to use the same file data env dat which was used in the native command analysis We see that the value is already set to what we want so we proceed The changes we are interested in making begin at line 66 We tell MOSES to use the vessel in the current directory in the file tow_brg dat Remember tow_brg dat was created to conform to the vessel library format Therefore this is all we need to tell MOSES when we use the tools The next two variables we set are the jacket starboard and the port nodes If we review the jacket dat file we see that nodes db4 and db2 have positive values in the y coordinate When we located the jacket on the barge with the native commands we did not rotate the jacket in any manner so the nodes on the starboard side would have a positive y coordinate This means that nodes db4 and db2 were placed on the starboard side The order that the nodes are placed in is important for these two variables The node listed first is conventionally known as the leading edge If we were to imagine that this jacket was to be launched the nodes at the barge stern would be at the leading edge into the water We see that nodes db3 and db4 have the largest x coordinate and would have been placed nearest the stern in the native command files Therefore in our install dat tool file
30. buoy the command amp describe body buoy md_force 1 0 0 is used This means total mean drift force will not include radiation and coriolis forces The documentation can be found at the following link http bentley ultramarine com hdesk ref_man bod_par htm For the buoy we are going to define the 8 fairlead points around the perimeter and the hawser connector These are listed at CAT1 to CAT8 The hawser connection is listed as TAUTB The mooring line description is similar to that used in the files mp_moor Connectors do not belong to a body It is a good idea to keep them in the buoy section since they do connect the buoy to ground The new option b_tension designates the breaking strength That concludes the buoy model edition A similar approach is taken with the tanker model The same approach for the mean drift force is taken A node x TAUTT is defined to connect the hawser Finally the connector between the tanker and the buoy is defined Again please remember that a connector does not belong to a body It is presented here as part of the tanker description because we needed to define the connection on the tanker before defining the connector Here are some views of what the system looks like at this point Page 94 Figure 39 System Isometric View Figure 40 System Side View Page 95 TANKER 300000 DWT MOORED TO A BUOY Figure 41 System Top View Many of the commands in the section
31. commands are stab_ok and kg_allow The command stab_ok asks MOSES Is the stability OK The command kg allow asks MOSES What is the allowable KG The stab_ok macro is used twice The first time is for intact stability and the second time is for damage stability Note that in the second time we are damaging com partment 5p see option damage 5p In both cases we are checking that the intact area ratio be larger than 1 4 and that GM is positive Output Discussion The log file has the familiar buoyancy and weight report The height of the non weathertight downflooding points is 13 ft This stands to reason since they were defined at 20 ft above the keel and the current draft was 7 ft Notice that for the stability results of the intact case two criteria are reported and for the damage case only one criterion is reported This is because for the intact case two criteria were defined and for the damage only one was defined Please keep in mind when using this macro that MOSES will only check what it is asked MOSES does not have an automatic list of criteria to check Page 35 Exercise A Use the same wcomp files as in the Basic Stability exercise The following are excerpts from the CFR Each unit must be designed 1 to have at least 1 inches of positive metacentric height Area a gt K Area B K 14 Area A is under the righting moment curve between 0 and the second intercept angle Area B is the ar
32. complete discussion on defining nodes http bentley ultramarine com hdesk ref_man geometry htm Next we define areas with their centers at bcg and ccg Notice that the names given to the nodes are your choice Here beg stands for barge center and ceg stands for cargo center Point names can be up to 8 characters but the x counts as 1 so you choose the 7 characters after the x Please notice that we defined the area perpendicular to the x direction and the area perpendicular to the y direction in different lines The area perpendicular to the y direction is 180 7 ft for the barge and 80 75 ft for the cargo The area perpendicular to to the x direction is 50 7 ft for the barge and 50 75 ft for the cargo In the following exercises you will be asked to verify the above two statements Towards the end of the file four more points are defined as non weathertight points That concludes the DAT file The commands in the CIF file should look familiar We see two instances of the amp status command In the first B_W is reporting the buoyancy and the weight and in the second nwt down the location of the non weathertight points is being reported We already have learned that the command amp instate sets the current condition Page 34 The command weight determines the weight so that the current condition is at equilibrium and the HSTATIC puts us in the Hydrostatics Menu The two new
33. current speed If you would like a more detailed discussion please see Wind and Current Force of Page 84 the verification document located at the following link http bentley ultramarine com hdesk document include verify pdf That covers the new parts of the DAT file Now for the CIF file The first new part is the section that begins with medit and ends with END_MEDIT Medit stands for model edit So we are going to alter the model For this exercise there is only one body TBRG in our model When we edit the model MOSES will default to TBRG If we had more than one body we would have had to use the amp describe body command to tell MOSES which model we were editing The first thing we do is define four nodes MLA MLB MLC and MLD If you look at the coordinates and look at the DAT file you will notice that the four coordinates are at the four corners of the barge These four points will be the fairlead locations where the mooring lines are attached to the vessel The next line that begins with a defines the class It is important that we under stand the concept of class This is how MOSES associates elements with properties Please review the entire section at http bentley ultramarine com hdesk ref_man cls htm I stress that the entire section be reviewed because there are many types of classes However we will only be dealing with flexible classes in this exercise We are going to use the flexible type b_ca
34. defined by the cross product of the new part x axis with the vector connecting PT4 to PT2 Finally the new part y axis is defined by the new x part axis and the new z part axis and the right hand rule Resetting the part axis for a part with the same name as the body also resets the body axis Now that we have reset the part and body coordinate system the reports that read Reported in the Jacket Body System will use this new coordinate system We are going to keep referring to joint J1001 to keep track of the jacket It would be a more complete analysis if we kept track of the whole lower plane However this is an example and we are not going to present that level of detail For the points we have designated the jacket part xy plane has the face nearest the water The origin is at the midpoint of the vector between j1003 and j1001 The x axis is from the origin toward the top towards midpoint of j0503 and j0501 The part z axis is vertical and the y axis is generated from the right hand rule The location of these points on the jacket model can be seen in Figure 11 The commands used to generate this view are shown below the figure Page 103 Sample of sidelift A van PAN DX Barty yal x BOs Vase as af Al A IA KW RR N Figure 45 Iso view of points used to redefine the part coordinate system amp select ppp select j0501 j1001 j0503 j1003 amp picture 90 25 0 render gl water no body jacket p
35. domain analysis is performed with the command tdom In the log file you will see the message Time To Set Up Convolutions Then MOSES reports when it saves the database and where it is in the event sequence The last message Simulation Terminated at Specified Time tells us that the time domain analysis computations are finished Note that MOSES has performed the calculations for the time domain analysis and stopped Reporting the results will occur later in the analysis In the next three commands we find when a slam occurred during the first 50 seconds As an input to the amp slam string command we need to know the name s of the parts that we want slam information For our analysis this just happens to be the one part jacket We made a selector here to show how selectors are used The next line amp type SLAM 1 to 50 seconds 2 sec increments Page 112 leaves a note in the log file to remind us of the start time finish time and time step The final line amp type SLAM amp slam lower 1 50 2 types into the log file the results of the string command amp slam This will leave a note and when we review the log file we see that slam events occurred at times 0 20 2 23 2 28 2 31 4 36 8 41 6 and 47 6 Now the question you are probably asking is Why is time 0 in the list If we read the manual bentley ultramarine com hdesk ref_man timdom htm we see that the list is a set of pairs where some elem
36. edition section medit In this section we are redefining the part coordinate system When we review the results it would make our life easier if roll was reported along the long axis of the jacket and pitch was reported along the axis at the base of the jacket and perpendicular to the long axis of the jacket Up to this point we have not taken any effort to determine the location of the jacket coordinate system Instead we Page 63 are going to use the amp describe part command to define the part system to fit our analysis The way we are going to use the amp describe part command needs a bit of discussion The command implies that you are changing the part coordinate system We need to be clear about what the rules are with the naming convention With a part system whose name is different from the body then only the part system is redefined With a part system whose name is the same as the body then the body and the part system are being redefined When you read the manual page on the amp describe part command you will see that the order of the nodes is important We want the x axis to be from the bottom of the jacket towards the top so that roll is measured along the long axis This means points 4 and 2 have to be at the base of the jacket and points 1 and 3 at the top of the jacket We next want y to be transverse on the base of the jacket preferably on the face floating at the water surface in the beginning event If you look at th
37. fenders This places the barge port side shell at y 29 35 For most commands it is acceptable to have the list of multiple options The same can be said about the amp weight command which follows These two commands have been discussed in previous exercises The only addition here is that we are using them to define properties of two bodies instead of just one Please note that this analysis progresses only through the static analysis therefore it is acceptable for the values for the radii of gyration to be left at 1 The generalized springs GSPR are connectors which means we need to add to the model Therefore we need to enter the model edit menu We enter the model edit menu with the command MEDIT As you may have guessed some of the commands in the model edit menu that we have thus far used in the data files will be used here to add to the model The first command which is familiar to us is amp describe body To define the points we use Page 80 the x This file also comes with notes imbedded within the file itself The first set of notes address some assumptions about how the fenders are going to work Here are the contents of the note NOTE Remember when defining locations for fenders compression only gsprs no force will be generated until the 2 nodes are touching Fenders should be located at the waterline alongside the ship so the point defined should be outboard the vessel by the diameter of the
38. files we only looked at three environment headings whereas the tools by default will examine eight headings The graphs that we can compare are the force response curves These would be graphics 6 to 9 in the native analysis and some of the figures shown in graphic files 14 to 21 in the installation tools analysis For the native commands analysis we did 180 deg graphic 6 135 deg graphic 7 and 90 deg graphic 9 In the installation tools they are done in a different order but they are graphics 18 17 and 16 You should be able to keep track of them by the graphic titles When you compare the curves you will see that so far we are getting the same answers for both analyses types You can also compare the numerical results in the output file In the output file we reported the force response at the jacket CG for just the wave s height and mean period that were specified These are the tables with the title CARGO G FORCE STATISTICS When making your comparison you will need to make sure that the information in the box outlined by s contains the same information Page 135 Sample Of Simple Jacket Installation _ Gs CG of JACKET For Unit Seas of Heading 90 ap 09 Long G Tran G Vert G 3 Roll A Acc p Pitch A Acc o Yaw A Acc ER S pe o Q z be E Q O ER Bs c c 2 2 5 5 E 4 S o o Gagi par o lt ig amp os m i SSS 0 4 5 4 68 8 2 96 1 12 4 13 8 15 2 16 6 18 FIGURE 17 Period sec
39. find the manual page that presents this command at http bentley ultramarine com hdesk ref_man bod_par htm amp DESCRIBE BODY Please note that we could have used the line continuation and placed both options after one amp describe body statement Both methods are acceptable Let s discuss the section option even though it appears second in the file The section option simply tabulates the section properties of the vessel The first number is IE Please note that the units would be the large force length squared kips ft mtons m or KN m Remember I is in Jength and E is in force per length squared The second set of entries is the longitudinal location and the section modulus at that location Remember section modulus is in ft or meters This establishes the properties of the barge The location option used prior to this simply tells MOSES the longitudinal locations We want the results of the strength calculation reported The next new option is the desc on the pgen command Here we are simply giving a bit of description to the part that is being generated Remember PGEN stands for Part Generator The last section may be new but for those adventurous types that looked through the transportation macros in more depth this may be familiar In the last section we describe a part that we name cargo As the name implies it is just cargo not Page 39 very descriptive The cargo is simpl
40. is 213 93 ft Next we check the tensions on the slings with amp status f_connector and find that the sling tensions are very large This is a result of the boom sling being shortened but the position of the jacket not moving to accommodate the shortened length The solution is to use amp equi again so that MOSES can reposition the jacket The results of amp equi show that the jacket has been moved and that the barge is still out of equilibrium by the same 189 kips Next we will check the position with the same string function amp point coordinate j1001 g that we did before We see the results now show that the position of joint j1001 is not 4 feet above the water line it is 1 foot above the water line The reason for this discrepancy is that when the jacket was moved with the amp equi command it was moved in all 6 degrees of freedom In our previous results of amp equi the jacket pitch was 11 94 degrees and now it is 13 62 degrees Now that we have resolved the pitch question we can conclude that the jacket is above water as desired Now we will deal with the barge out of equilibrium issue For this we bring the barge back into the calculations To take the barge out of the calculations we used the command amp describe body barge ignore x y z rx ry rz To bring the barge back into the calculations we use the command amp describe body barge ignore When the option ignore is used and the space after it is left blank i
41. model editing needed for launch In the automated method a section of the output is dedicated to reporting the model Here we are just going to report the summary of the restraints and a short category Page 149 summary of the jacket amp summ restraint cat part jacket end It is a good idea to run the analysis and have the log and output files available for discussion The restraint report contains some unexpected entries We defined the launchway assembly with the command assembly lleg the first row of the report shows an element with name amp LR1 001 and a class of amp LRUNNER connected to to xJ0006 A launchway connector is a really a complicated connector The ends of the connector on the barge have to change and eventually remain turned off when the jacket enters the water Having the user input all these connector specifications would be very time consuming and prone to human error This is the default naming and numbering scheme done within MOSES The last row shows the spring restraint that was part of the data file The Category Summary for Part Jacket you should be familiar with A similar report was presented as part of the transportation exercise The next set of commands you may be mostly familiar with amp INSTATE barge condition 0 0 3 amp weight compute barge 10 32 0 29 330 0 29 330 amp status config amp status g_lway amp picture side The only new command is amp status g_Iway This command g
42. nodes db3 and db4 are listed first for the variables To define the port and starboard nodes we have amp set port_nod db3 db1i amp set stbd_nod db4 db2 This is just the first part in defining the jacket location and sea fastening The command model_in is next used to locate the jacket on the barge Remember that in the native commands we also placed the jacket coordinate system origin at 200 feet in the x direction The z coordinate is what is different Part of the barge library format is to input a variable vdepth which is the distance from the barge deck from the keel Therefore the distance used to locate the jacket in the z direction is taken from the barge deck In the native command file we located the jacket 25 ft from the keel but for the transportation tools we will use 5 ft from the deck The two options used for the command model_in use the port and starboard nodes we just designated port_nod and stbd_nod have the syntax of options however for Page 133 this command they are necessary they are not options Using the options port_nod and stbd_nod we tell MOSES to place nodes db3 and db4 nearest the stern of the barge and place nodes db4 and db2 on the starboard side and nodes db3 and db1 on the port side of the barge For now that is all we need for locating the jacket on the barge Next we will define the supports and sea fastenings The next set of commands looks very similar to those
43. once it provides a clean way to write the commands and they can be referenced in the output After this we enter the frequency response menu and calculate RAOs and report RAOs at the system CG When we calculate the RAOs at the jacket part CG we do not ask for a report Then we calculate the force response operators for the cargo which happens to be the jacket and again we do not output the results This is back to the idea that we are trying to produce the same set of output as the installation tools do The next part where we report the G Force Statistics is where we do write reports The reporting of the G Force statistics is done in numerical and in graphical form In the output file the statistics are listed just for the nine environments defined earlier In graphical form the period of each of the environments is presented from 4 to 18 seconds This second part is done with the e_period option This concludes the frequency response portion of the analysis Next we perform a structural analysis Page 130 Native Command Structural Solution Before we begin the structural analysis we reset the active environment to none and we take out the subtitle This is done to keep the output easy to read The structural analysis presented in the native command file is the basic approach to a transportation structural analysis The installation macros contain a great deal of logic that better represents the project progression T
44. option mean yes What changes in the Connector Force Statistics report when this is changed to mean no Page 79 5 2 Modeling a Fender Topics e Working with the Model Edit menu e Working with Generalized Springs Reference files fender cif fender dat These files show how to use generalized springs to model the connection between two bodies The two barges are positioned along side each other the centerline axes are parallel Generalized springs are used to define the fenders between the two vessels A short command sequence to test the fender definition is presented The data file is two rectangular bodies The user should be familiar enough with the modeling language so as to not need this file explained Please refer the stability check exercise presented the modeling language if you are unfamiliar with the language presented in the fender dat file Discussion fender cif This is the first time we set the location of two bodies with one command You can see that the amp instate command is used with two locate options The barge beams are 15 85 meters for body barge and 27 3 meters for body tanker The minimum distance between the two is 43 21 15 85 27 3 meters The instate command leaves the centerline of the body tanker at x 0 and y 0 in the global coordinate system and leaves the centerline of the body barge at x 180 y 45 2 m in the global coordinate system This definition leaves a 2 meter distance for the
45. output for the launch analysis This is actually a quick way of producing LAUNch Process STanDard output The reports it creates is Location of the Origin of Selected Bodies Velocity of the Origin of Selected Bodies and Skidway Reacations reports It also creates the plots in the answers directory These are the plots that we have noticed many MOSES users find helpful in evaluating the launch process Certainly knowing the bottom clearance is helpful as shown in Figure 60 Barge and Jacket Clearance Knowing the jacket slides off the stern instead of tipping off a side is helpful as is shown in Figure 61 Vertical Force at Pin and Trailing Edge is helpful Sample Launch ea Ss Ping tbd Trailin e Port Pin g Port Trailing Edge 2 43 10 3 192 189 248 mA pe Vertical Force Kips pe a p og 1 98 x p 0 54 0 27 or T T T T T 0 7 3 146 21 9 29 2 36 5 43 8 51 1 58 4 65 7 73 Time Sec Figure 61 Vertical Force at Pin and Trailing Edge In the next long section we solve the structural solution three different ways The three ways are Approximate Solution Better Solution Before Tip and Combining Both You might recall the general format for the Structural menu from the Lon gitudinal Strength Part 2 exercise Because this is a two body body problem and Page 152 becuase we are using launchway connectors we have a few more commands In al
46. starting ballast and the flag to set the compartment to dynamic flooding have to be placed right before the tdom command The actual time domain calculations are performed with the tdom command Please note that the tdom command is a Main Menu command and at the conclusion of the time domain you are still in the Main Menu This is different from the frequency domain calculations where it is all performed within the Frequency Domain Menu As mentioned earlier a time domain analysis is a process In order to view the results we need to be in the Process Post Process Menu prcpost For any analysis in which there is a process you will be able to use this menu In general the sub menu trajectory should be available for all of the analyses in which there is a process The other menus we will use here are generally only available for Page 60 similar analyses as we have here The sub menu draft works with the draft marks we described in the DAT file For future analysis in which you are interested in how the draft changes with events you will need to describe the draft marks similar to how we did here Since this is our first venture into this menu I will use specific examples but in general a process can have many different configurations The specifics that work in this example will probably have to be changed if you look at a different process The sub menu categories are tank_bal hole_flood tank_fld and are generally available wh
47. structural analysis Like many processes in MOSES we need to first perform the analysis then ask MOSES to report the results So we exit the Structural Solver Menu with the command end To post process we enter the Structural Post Processer Menu with the command strpost Once inside the Structural Post Processor we ask for the results of the beam code check with the command beam_post code_check and a summary of the restraint loads with the command restraint loads We see from the WS Beam Check Standard table that the loads created by event 5 dominated for many of the beams Page 117 Exercise A Perform statistics on the time domain connector force boom and slings results Compare these to the frequency domain results Suggested Answer conforce vlist statistics 1 24 32 40 48 56 hard end The statistics of the boom and slings are reported in the output file Remember to compare proper values The period is 8 seconds The frequency do main reports the mean maximum response so that should be compared to the Maximum and Minimum values from the time domain The output is shown Ten Brk 1223 0982 4472 3694 2191 3009 3884 below Frequency Domain Period Name FX FY FZ MX MY 8 00 AIRT1 17 68 103 97 35 32 0 ie AIRT2 27 21 13 19 41 04 0 0 BOOM 64 34 362 43 1414 90 0 0 SLING1 159 49 272 54 487 46 0 0 SLING2 125 66 297 68 403 66 0 ie SLING3 359 63 237 81 344 28 0 0 SLING4 383 80 235 3
48. that the jacket stays with a face near the waterline until near 65 seconds Then the jacket begins to roll until it rolls past 90 degrees and the program shuts it down Exercise A Restart sink analysis and at the bottom window type the commands prcpost trajectory vlist Hit ENTER at the end of each command Note the title bar changes to show what menu you are in After entering the command vilist we get a list with 24 entries From the resulting list we know 1 corresponds to time and 7 corresponds to Z TBRG Z TBRG is understood to be the Z location of the barge coordinate system origin measured in the global coordinate system This helps you understand the numbers after the plot command In the CIF file the no option is used with the plot command The no option tells MOSES that there are no editing changes to the plot that is to be produced 1 What is associated with 9 2 When you look at the plot in the sink ans directory gra00001 png e What is the legend on the x axis e What is the legend on the left hand y axis e What is the legend on the right hand y axis RAX 3 When you review the plot command in the manual what command do you need to make a plot with the independent variable to be labeled with EVENT the left hand axis Displ TBRG and the right hand y axis to be labeled with Bot Clear TBRG Page 66 Exercise B The sink command file contains a section for reporting the t
49. that we used in the native cif file To define the support cans and the seafastening tiedowns we will be using the i_connector command several times Within the transportation tools the i connector command and the designators used after it tell MOSES what part is being defined the orientation and the connection points The support cans are defined with the i_connector v_can command Please note that for the transportation tools we were able to list all of the nodes that will be supported on one command line This is different from the syntax used in the native cif file The classes are defined with the same command as in the native cif file MOSES knows to define a part with a CAN name when a connector is defined using the designator v_can The tiedowns are defined with the lines that contain the pconnect command These are basically the same commands from the native cif file with the command i_connector before the pconnect MOSES knows that when the command i_connector pconnect is used that a tiedown part is being defined This is all of the information that is needed to produce the same model as the native cif file In the default install dat file that is located in the download site there are still several commands after the tiedown definition Since they are not needed for the comparison we will not be discussing them here Command file install cif There are few changes needed to the install cif file to produce the analysis performed
50. the environment Usually the meteorologist will have this information You will need to somehow put it into this format Remember this file is inserted while we are in the structural post processing menu When we end out of the duration menu with end_duration we can just create the fatigue load case with the command cases Then when we return to the native cif file we just ask for the fatigue report with beam fatigue After this we exit the structural post processing menu with the command end The last thing we do is create a picture of the structural solution The command amp picture iso type struct color ratio creates a picture with the color of each member of the jacket indicating its value in the structural analysis unity check This concludes the transportation analysis with all of the MOSES native commands Next we are going to use the transportation tools to do the exact same analysis Automated Installation Tools Page 132 If you have not read the online documentation for the installation macros please see the following link http bentley ultramarine com hdesk ref_man install htm Our discussion will start with the files from the download site install dat and in stall cif We are going to start with the install dat file Command file install dat The top part of the install dat file sets many variables which are self explanatory wdepth is for water depth the SCFs to use are from Efthymiou etc The variable we
51. the panel model be the same length as the structural model It would be nice for MOSES to report check this and report it as an error if it did not match Add some checks so that when the length of the structural model does not equal the panel model an ERROR is reported In the data file add after the panel model amp set vlength 400 In the data file add after the structural model amp set str_len amp number real num_beamsx dist amp if not strlen eq vlength amp then amp error ERROR Structural model length different from panel model amp endif Exercise B This exercise shows how to use some of the graphics options 1 Restart the analysis 2 From the main menu click on Graphics 3 From the sub menu click on Picture Options Page 54 T 8 This will bring up the Picture Options pop up window On the View tab under Picture type select Structural and under Render Type select Solid On the Misc tab make sure the box next to Show Water and World is blank Then first bring down the menu with Show Deflected Shape and select yes This will add a cell for Deflection Multiplies Input 100 This brings up a structural picture of the barge with the deflection magnified 100 times Page 55 3 Convert from SACS 3 1 Translating from SACS Topics e Introduction to translating from SACS e Checking the model Reference files sac_tpg cif sac
52. to examine the residuals For very large bodies there are times an equilibrium is not found but the analysis can continue The reason we find an equilibrium position is that we need the mean static offset position We need the vessel to be placed in a position where the mooring system forces equal the mean environmental force For this sample at the conclusion of this section the vessel is at the mean static offset position When you are doing your own mooring analysis you will need to stop MOSES here and verify that the mean offset position is acceptable The next section has been labeled Define Report Points Depending on what our task is we may be interested in all of the points or just a Page 87 few points For this analysis we are just interested in reporting what happens to the four fairlead points So we have told MOSES that the interest points all begin with the two characters M The sign is the wild character in MOSES Not only is it the wild character it also means that any number of characters can be substituted All of the MOSES special characters are discussed at http bentley ultramarine com hdesk ref_man cmd_menu htm Dynamic Analysis Discussion The dynamic analysis portion of the file is separated into the linear frequency domain analysis the spectral frequency analysis and the time domain analysis Now take out the amp eofile used for the earlier exercise and run the entire sample The discussion will inclu
53. to report the statistics at a point and connector forces So st stands for statistics Here we only reported the motion statistics at a point and connector forces There are other statistics that can be reported Please see the manual command index to get a listing Notice that each of these commands enter you into the Disposition Menu MOSES will perform the calculations but if you do not ask for a REPORT MOSES is not going to give you the results Also notice that you need to END out of each disposition menu You need to END out of the Frequency Response Menu too Dynamic Time Domain Analysis Discussion Now let s talk about the Time Domain There is also a discussion on the website at http bentley ultramarine com hdesk runs c_htm tdom_com htm You will notice that the command structure looks very different The command TDOM is a Main Menu command Please refer to the manual for remarks on the NEWMARK option If you examine the log file you will see that there are twenty messages about the database being saved Having brought up the subject of databases this naturally leads into questions about time step choice total time choice and many others Because a time domain simu lation can be performed on many configurations it is difficult to address all of the possible answers one may have on this subject I would like to refer the reader to the FAQ on Time Domain http bentley ultramarine com hdesk question time htm In the
54. used as part of a beam definition becomes a node and a node used to define more than one beam is a joint The terms point node and joint will be used interchangeably For the jacket all of the nodes points begin with d There are a total of eight points defined to join 12 members Only 6 of the members were given names all starting with b Point db0 was set at the origin x 0 y 0 and z 0 The jacket is part of the body tow_brg In jacket dat line 6 reads amp describe part jacket Native Commands Method Model data file native dat The file native dat consists of two commands amp insert tow_brg dat and amp insert jacket dat When we view the two files we see that the order of files in native dat is important For this analysis there is going to be one body tow_brg The body tow_brg con sists of two parts names tow_brg and jacket The body tow_brg has to first be established before any parts can be added This is why order is important in the file native dat Command file native cif Now we will discuss the command file As with other files the model is read with the inmodel command For this inmodel we are using the offset option This tells MOSES to take out any extra steel that is in the computer model that would not be in the real world That is to say the tubular beams are defined from node to node However when they are welded the steel will have to b
55. visual guides This extra body is named ZZZGLOBAXES For right now we are just going to acknowledge that it exists We will talk about it later Next the barge is defined First the outer shell is defined then a crane using structural elements and finally some points of interest and a selector The last section is the jacket model This is the same jacket model used in the up_lower sample Many of the commands used to make the model have been discussed earlier The last two lines also designate points of interest this time for the jacket body Once the bodies are completely defined we can begin setting up the analysis Page 102 Sidelift Command File Discussion Connecting the Two Bodies The command file starts with the familiar commands that start a command file The dimensions are set and the model in the data file is read The command file itself is heavily commented The discussion here is intended to complement the comments already in the file The first new command resets the coordinate system for the jacket part This is done with command amp describe part jacket move 0 0 0 j0501 j1001 j0503 j1003 If you read the manual page on the command describe part you will see that the point order is important for this command Here we have PT1 j0501 PT2 1001 PT3 j0503 PT4 j1003 The new part x axis will be from the midpoint connecting PT4 and PT2 to the midpoint connecting PT3 and PT1 The part z axis is
56. with native cif Remember this discussion assumes that you are starting with the install cif file from the download site The first set of changes are in lines 12 to 16 We are only interested in the trans portation analysis This should be the only variable left with a value of true Please note that the values includes the before and after the letters The values for launch loadout upend and lift should be set to false The other section we want to change are the options used on lines 33 to 36 In the native file we used wave height and period pairs 5 and 10 4 and 11 and 6 and 12 In the native files we had to specify what headings to look at In the installation tools all we have to do is list the Hs and period pair The installation tools take care of making the environment descriptions for 8 headings 45 degree spacing The options wind w_inctact w_damage w_vortex w_stuctural tell MOSES which wind velocity to use for the different parts of the analysis We tell MOSES to use 100 knot winds for intact stability We need a value for damage stability Even though for our analysis we will not be performing damage stability a 40 knot wind will be used to check vortex shedding and 0 knot winds will be used for structural analysis The Page 134 installation tools check vortex shedding by default We did not include wind when we defined our environments in the native command analysis That is why we are also not goin
57. with the command end In this next section of commands we write several summary reports to the output file The objective we are trying to fill with these reports is to provide verification to the project that the correct model was used and that we are providing them to parallel the output from the installation tools Using the command amp rep _sel part partname allows us to present the data that is relevant just for the part we are interested in for verification This makes the output easier to read and hopefully reduces the questions from people reading our results For the barge all that we report is a Piece Summary This report provides a very short summary on the vessel particulars For the jacket we report Category Summary Wind Vortex Shedding and Beam SCFs For the transportation analysis there is one body and two parts If you review the output page 3 and shown below in Figure 5 with title CATEGORY SUMMARY FOR PART JACKET produced with the command compart_sum piece you should also see that the values are reported in the part coordinate system If you remember the barge part coordinate system has its origin at the intersection of the bow center line and keel The jacket has the part coordinate system origin at point db0 which right now is located at barge body location x 200 y 0 z 25 If you look again at the table you will notice the column headings indicate where the center of gravity and the center of buoyancy are f
58. 0 379 56 0 0 Time Domain MAG MAG MAG MAG MAG Description BOOM SLING1 SLING2 SLING3 SLING4 Mean 1151 32 335 45 340 27 336 33 346 28 Av Of 1 1000 Highest 1770 63 639 58 614 43 581 25 492 39 Av Of 1 1000 Lowest 379 77 73 58 77 51 126 03 150 18 We see that the magnitudes of all connectors are greater in the time domain Page 118 Exercise B There is also a command p_min_dist We need to make some changes for it to work In the data file in the barge definition line 41 change it to read pgen barge cs_curr 1 1 1 cs_wind 1 1 1 tanaka 0 In the data file add to then end amp select jjj select j To the command file add the following to the end prcpost p min_dist barge jjj vlist stat 1 2 end end Compare the minimum distance to the one qe calculated earlier just keeping track of 3 points Did you notice this took the computer a long time to calculate Page 119 Exercise C Perform relative motions and slamming calculations plots without loop or the amp build_g menu Suggested Answer amp set bang fal se start off assuming it does not bang rel_motion edgel j1003 edge2 j1003 edge3 j1003 mag x y vlist set_variable set_variable set_variable amp set bangi amp set bang2 amp set bang3 kif not amp if ba amp set amp elseif amp set amp else amp set amp endif amp endif plotting ind plot 1 5 plot 1 17 plot 1 29 cedge1 min 5 5 cedge2 min
59. 17 17 cedge3 min 29 29 amp logical cedge1 1t 0 amp logical cedge2 1t 0 amp logical cedge3 1t 0 bang amp then ngi amp then bang true bang2 amp then bang true bang3 amp then bang true ividual curves t_sub Relative Position ae ce Time sec t left Distance edge1 j1003 t_sub Relative Position tx Time sec t_left Distance edge2 j1003 t_sub Relative Position tX Time sec t_left Distance edge3 j1003 plotting combined curves plot 1 5 end 17 29 t_sub Relative Position at Time sec t_left Distance to j1003 legend 1 edgi legend 2 edg2 y legend 3 edg3 Page 120 6 Advanced Exercises This is the advanced section of the workbook It is assumed that the reader does not need to be given a link to the commands in the MOSES reference manual It is assumed that the reader needs a discussion on the command structure The exercise discussions from here on will focus on why the commands chosen were put in the order they are presented and what project questions were being addressed In this section you will find commands where I refer to my own preferences I have tried to be careful and always say that I prefer or the only time I when I am expressing my habits I am being careful here because these are my preferences and they will not necessarily apply to your situation or you
60. 6 6 66 6 8 Figure 46 Results of amp status config command The next three reports cl_flex g connector tip hook show details of the connector classes connector geometry and sling assembly geometry respectively It is also a good idea to review the buoyancy and weight report This is what is presented with the results of the amp status b w command This report shows the weights buoyancies and their centers From the results of amp status b_w we learn that the jacket weight is 1190 kips We are going to continue the search for static equilibrium and we will continue to produce these tables until we are satisfied that all of the results can be explained In the next command amp connector amp boom l tension 1000 we change the boom length until the tension is 1000 kips This is the maximum capacity of the crane Right after changing the boom line length we ask for a report of the forces in the connectors amp status f connector This shows us that the force in the boom sling is 1000 kips However the vertical force in the slings sums to 988 kips 310 7 310 7 183 3 183 3 Also the amp status configuration table shows the jacket to be 188 kips out of equilib rium which we know the slings were not holding So what s up Notice that the forces are reported in the body coordinate system Since the jacket has a 9 degree pitch Z_body is NOT parallel to Z_global If we do the math the force of the jacket in the globa
61. 6ft depth 15 ft e The CG is x 142 y 0 z 20 e The cargo weight is 1000 kips You are to add the cargo and empty compartments 4p and 4s You are asked for an updated stability and RAOs This is the suggested addition to the DAT file The answers in the answers section are based on these changes amp describe part cr_strn cr_strn 0 0 20 WEIGHT cr_strn 1000 16 16 20 pgen cr_strn perm 0 cs_curr 1 1 1 cs_win 1 1 0 plane 25 20 15 10 0 10 15 20 25 rect 15 30 66 end_pgen Changes to the command file INMODEL medit amp describe body cbrg180 amp describe part cr_strn move 14200000 end_medit amp compartment percent cbrg180 0 3p 100 1 0255 3s 100 1 0255 1p 100 1 0255 1s 100 1 0255 Page 70 1 Did the range change in the stability results What is the range 2 When you present the results are you going to make a comment about the resulting condition draft roll trim Page 71 5 Connectors Connectors are mainly used to transmit a force or moment from one body to another The amount of force or moment is dependent on the connector definition In this section we present a variety of connector types and a variety of uses Page 72 5 1 Sling Assemblies Topics e Introduction to sling assemblies e Defining macros e Working with more than one body Reference files two_blk cif two_blk dat wp_lower cif up_lower dat spread cif spread dat The presentation here is meant to show a progr
62. 8 88 549 40 Figure 20 Results After the KG ALLOW command The report before kg allow shows the weight amp DEFWT with a ZCG of 5 00 ft the report after the kg_allow shows the weight amp DEFWT with a ZCG of 17 12 ft and the VCG of the barge system at 15 95 ft This answers the question from above If we want to know the allowable KG for the system we have to somehow turn off the L SHIP weight Exercise B Find the allowable KG of the system You are looking for an allowable KG for a 6 ft draft Check both intact and damage comp 5P and for 0 and 45 degree yaw You will need the following command to turn off the category l ship amp apply percent cat l_ship 0 Page 38 2 6 Longitudinal Strength Topics e Parts defining and positioning e Difference between equi and amp equi e Define a point load and a distributed load Reference files p_m cif p_m dat Discussion The reference files are in the test directory under the hydrostatics tests The reader should be familiar enough with the web page at this point to be able to locate these files and place them in the directory in which they will be working Both of these files are rather short Most of the discussion will focus on options for the command we are already familiar with We will start by discussing the DAT file The first new option we see is the location and the section being used with the command describe body The reader can
63. Estimated BLWAY Dimension Using Estimated XTPIN Dimension Using Estimated HEISKD Dimension Set Variables in INSTALL DAT File if Known Time To perform Inmodel gt setup Defining Upending Tanks xxx WARNING No Objects Selected by S Box Weight CG 1866 6 66 6 66 Box Radii 1 66 1 66 Box Max Buoy 6 Time To Set Up gt inst_transp wind 83 19 56 166 166 draft 6 trim 53 damage 1s 25 35 4s Ss no_seakeeping Time To Compute Distributed Barge Ballast CP 6 26 Time To Write Summaries CP 6 61 Computing Righting Arms Time for Righting Arms Process tranja Nominal Condition xxx WARNING BALLAST CANNOT FIT IN THE BARGE FOR THIS CONDITION MOSES Finished with 4 Warnings Figure 18 Messages in the log file Page 32 Now let s look at the out file This first section through page 10 is part of the standard output generated with the automated installation macros The Model Size and Program Parameters let us know a little about the problem we are solving The External Piece Summary tells us a bit about the barge CBRG180 piece MAIN and the piece BOX We see that the barge does not attract wind loads and therefore our stability may be underestimating the wind arm The Category Summary for Selected Parts tells us the same things that the log file did about the BOX model The Class Dimensions Material and Redesign Properties and Class Section Data tell us about the parts MOSES had to estimate In the DAT file we
64. TION In there we find that The results are expressed in the body system of the first point This is important to note The results are dependent on what coordinate system is being used For this analysis it is very important to avoid collision It is a good idea Page 99 to look at the minimum distance from several reference points Exercise A What is the minimum distance based on the tanker coordinate system x y plane What is the minimum distance based on the buoy coordinate system x y plane Exercise B 1 Find the location of tautt and tautb at event 1 2 Find the global position of the buoy and the tanker at event 1 3 Change the relative motion section so that only the first 4 events are reported Can you justify with geometry the difference in the two results Page 100 5 5 Sidelift Topics e Tip hook assembly definition e Frequency domain motions analysis Time domain motions analysis Reporting relative distance between two points Structural analysis of suspended jacket Reference files ultra hdesk runs samples how_to sidelift cif sidelift dat Overview Discussion This set of files shows how to perform a sidelift motion and structural analysis with native MOSES commands There is a boom hook sling assembly defined to connect the two bodies barge and jacket The jacket is held just above the water The two body system is first put in static equilibrium then the dynamic analysis is performed in b
65. The MOSES model is provided We will need to use a command file similar to ck_sac cif to determine which nodes are at the top and bottom of each leg We will also need the ck_sac cif file to determine the order of the nodes After clicking some we find that the nodes at the ends of the legs are JO101 and J0401 we will call LEGA J0105 and J0405 we will call LEGB The instructions call for LEGA nodes to be parallel to the barge Page 141 side shell with a positive y coordinate This means that LEGB will be on the port side The nodes at the top of the jacket are J0401 J0403 J0407 J0405 The instructions tell us the distance from the bow to node JO101 is 15 meters This means the top of the jacket will be nearest the stern To orient the jacket with one leg parallel to the centerline or sideshell we use the orient option This is the same option we used for the deck with odd number of legs Figures 55 to 36 show the transportation configuration The manual instruction for orient are For a structure which is not symmetrical about the barge centerline the orientation scheme is different Here the orient option is used This option defines three nodes The first node is where the distance for po sitioning will be measured and is normally at the bottom of the leg that is parallel with the deck edge assuming the top of jacket faces aft The second node is along the leg from the first node and the third node is on the other side of the
66. Use the name cow cow without the quotes After a few seconds the main menu will appear at the top of the screen Use the pull down CUSTOMIZE menu Select Register with OS Close MOSES by typing amp FINI in the command prompt You should now be able to double click on any cif file on the machine and have MOSES run Page 3 2 Hydrostatic and Lontudinal Strength 2 1 Getting Started Exercise Topic e Introduction to basic MOSES commands e Demonstrate how to restart an analysis and make modifications Commands to use MOSES b_run Setup Analysis Run ultra hdesk started b_run b_run cif and b_run dat Discussion Running MOSES In this exercise the student will become familiar with the file structure and run a simple analysis At this point we are not interested in understanding every command just the concept of menus For a list and discussion of the commands found in most examples please see http bentley ultramarine com hdesk runs c_htm common htm A discussion and screen shots of the process are also presented at the following link http bentley ultramarine com hdesk b run brun htm If using Windows you should double click on the file b_run cif The file b_run cif should have an icon that looks like a parabolic shape inside of a half rectangle Once you double click the CIF file the MOSES window should appear and the analysis commands scroll by This should take a few minutes at most When the MOSES window disap
67. We are not trying to fully scrutinize the response The command fr_point makes any necessary final calculations to translate the motion RAOs to the point specified Notice that after each fr_point command you are placed in the Disposition Menu Within the Disposition Menu the command report generates the standard motions RAO report and puts it in the output file In the out file you have two reports titled MOTION RESPONSE OPERATORS The third line of each report reads Of Point On Body body name At X 0 Y 0 Z 0 where body name is either BARGE or JACKET The reports show the calculated values for the RAO of each degree of freedom These values include both amplitude and phase When we review the results of fr_point we see that the peak response of the barge for sway and heave occurs at 11 seconds while the peak response for roll and pitch occurs at 8 seconds The peak response of the jacket for sway occurs at 9 seconds while the peak response for heave and roll occurs at 8 seconds Page 110 The reports of the JACKET RAOs are really response amplitude operators they are not the results of hydrodynamics on the jacket The JACKET is being forced via the motion of the tip hook and sling connectors For now that is all we are interested in Exit the Disposition Menu with the command end which puts us back in the Frequency Response Menu We next report the motions of the point designated in the fr_point command We do this wi
68. We do this with two command lines in the command file It could be done with one This way we get to see how to make selectors with the wild character First we make a selector air with the command select air select airt This will create a set of items that begin with airt The command amp connector air inactive turns off inactivate the airtuggers This way when we ask MOSES to find equilibrium for the jacket only the sling forces the weight and buoyancy of the jacket are used Previously we ensured that the barge is in equilibrium Now we want to exclude the barge from any changes when the jacket is being altered for equilibrium The amp describe body barge ignore x y z rx ry rz tells MOSES to ignore the barge when calculating equilibrium The command amp equi will change the position and orientation of the jacket with the objective to find equilibrium This command makes 50 attempts at finding equi librium If equilibrium is not found within tolerance it will report a WARNING message At the conclusion of the equilibrium calculations the command amp status configuration produces a report which shows that the jacket body is in equilibrium but the barge body now is not in equilibrium We also see that the vertical position of the jacket has changed moving the jacket into the water Since part of the jacket is in the water the tension in the slings changes which in turn causes a change in tension in the boom
69. _tpg dat ck_sac cif ck_sac dat cnv_ck cif jacket sac Discussion the long way The reference files are in the tests directory under the directory convert The reader should be familiar enough with the ultra directory MOSES installation directory at this point to be able to locate these files and place them in the directory they will be using Here we present the procedure to convert a SACS model to MOSES format and a suggested method of checking that the conversion was done correctly Converting a model is a simple exercise It is the checking that needs to be done carefully If you look at the sac_tpg dat file you will notice that the first line is a MOSES command and until near the end all of the commands are SACS commands The MOSES command at the top reads amp convert sacs jright 000 cright 000 Please see the manual page on amp convert for a more detailed explanation of the com mand and the options The last two lines of the file are END and finish The END command is the last SACS command and the amp finish command is the MOSES command These two lines are all you need in the data file to convert Now let s look at the CIF file The CIF file has three lines The first line is really not needed for the conversion to work it is put there to make the output easier to read The command amp device oecho no tells MOSES not to echo the data file to the output file Please recall that in most of the previous exercises
70. a launch analysis in two methods The analysis is done with native commands with a simple jacket model Then a more real jacket model is used with the installation tools The analysis done with the installation tools is considered more complete The objective in presenting both methods is to show some of the steps that the tools are using and to show that if you wanted to go the long way you could Many of the native commands needed for the model summary reports were presented with the native transportation exercise The discussion on those commands will not be repeated here For the native launch commands the files are under the tests install directory They are man_laun cif man_laun dat and ji_barge dat For the automated files we will use the same files used in the automated transportation exercise Discussion Native Files A launch analysis is a two body problem The jacket body slides off the barge body Much care needs to be taken so that the pre launch condition is defined as the project desires Most of the discussion here for the long way concentrates on setting up the pre launch condition For this exercise a translation from SACS is not needed The MOSES model is provided There is a restraint at the end of the file that is needed SPRING FIX REST SPRING J0001 This restraint is needed so that the structural solution will solve We will need to use a command file similar to ck_sac cif to determine which nodes
71. al model has the XCG at 225 ft from the bow This makes sense because the jacket is located at x 200 and the XCG in the jacket part system is at x 25 ft The structural weight that is reported in the Category Summary report on page 17 includes the jacket tiedowns and cans Also please note that the command amp weight added a negative value to achieve equilibrium The weight added by amp weight is presented as amp DEFWT That concludes the static analysis portion of the transportation analysis Next we do the hydrodynamics and the structural analysis Native Command Hydrodynamic Analysis Creating the hydrodynamic database has been covered in previous exercises Basi cally the same set of commands are presented here Please refer to the previous exercises for a discussion on the commands The environments we are going to use need to be given a name The easiest way to do this is in the amp data environment menu We are using the same naming convention as that in the installation macros The first character is a letter designating a Hs and Tm pair followed by three characters designating the environment heading Notice that the syntax used for environments in the amp data environment menu is the same syntax used for the amp env command We are going to be using the same environment descriptions for the motions analysis and the structural analysis Defining them by giving them names reduces any human error because they are only defined
72. alues we set in the long method but with values appropriate for this barge Page 158 and jacket amp if launch amp then inst_launch friction 06 draft 5 49 trim 2 95 nonlinear winch 5 amp endif Just like in the long method the friction and the winch speed are defined For the long method the condition of the barge was set with amp instate condition here we are using the draft and trim options Please be careful and read the instructions For this option the draft at midships is being defined The last option nonlinear tells MOSES how to model the launch way connector during the strctural analysis This is all that is needed in the automated method Here are a fews of the standard plots that are created Sample Of Simple Jacket Installation RAt Tip Draft 5 49 M Trim 2 95 Deg Event 109 5 FIGURE 12 Figure 67 Side view of Tip Event Page 159 Sample Of Simple Jacket Installation RAt Seperation Draft 5 49 M Trim 2 95 Deg Event 118 3 FIGURE 13 Figure 68 Side view of Separation Event panpe Of Simple Jacket Installation Launch From Mid Drit 5 49 M Trim 2 95 Deg ay f a Jacket Roll o Jacket Pitch a Jacket Yaw y ERM l bd Bere Yaw P pen ee SS x o v ka v ki ge Angles al i s Bari al i 0 16 32 48 64 80 FIGURE 6 Time Sec Figure 69 Trajecto
73. and the jacket to transfer forces from the jacket to the barge The file also contains comments to explain what is being done The discussion is meant as a complement to those comments This discussion assumes that the reader has the data command log and output files available Many of the commands used have been discussed in previous exercises This discussion assumes the previous exercises have been read Model data file tow_brg dat and jacket dat The same barge and jacket data files are used for both analyses The barge data file conforms to the requirements for being in the MOSES library To see the requirements for being in the MOSES barge library please go to the following link bentley ultramarine com hdesk tools vessels vessels htm This is a rectangular barge length 300 ft width 90 ft and height 20 ft Only the outer shell was included in the definition It has five points defined with Page 122 the name beginning with a v The origin of the barge is at the intersection of the centerline bow and keel The body has a name of tow_brg You will see that in tow_brg dat line number 71 the command reads amp descirbe body vname In the file tow_brg dat you will need to return to line number 38 to see that the variable vname has been set to tow_brg The jacket is a space frame that looks like a square The jacket is made up of 12 members only 6 of them were named There are eight points defined A point
74. ank flooding tank_f1 report end Add this section to the up_ damage command file When you review the output file for both sink and up_damage you will notice that the columns for Extrnal Fl Head Internal Fl Head and Vlv Diff Head are blank for the active compartment This is caused by the time domain ending abruptly When the time domain ends due to capsizing MOSES interprets this as a failed analysis and tries to bring attention to it There is a message in the log file and this blank in the report that specifically show what is happening with the dynamically flooded compartments In order to avoid this the time allowed needs to change to something smaller than when it capsizes In the sink command file change the environment command so that the time simulation ends at 200 seconds In the up_damage command file change the environment command so that the time simulation ends at 80 seconds amp env null time 200 1 1 Is there a change in the log file 2 Is there a change in the Compartment Flooding Report Exercise C In the up_damage command file change the flooded leg to be leg 2 the one associated with compartment two From the locations of the valves you should be able to determine that leg 2 is the leg not at the water surface When this leg floods the trajectory looks more acceptable to a controlled upend procedure Page 67 4 2 Basic Frequency Domain Motion Topics e Calculating RAOs e Reporting motions a
75. ansportation variables to true This is lines 8 through 12 amp set launch true amp set transportation true amp set loadout false amp set upend false amp set lift false This will run the transportation and the launch analysis in one MOSES session The automated files will take care to define one body consisting of the barge and jacket part for the transportation analysis Separately it will define a body jacket and a body barge for the launch analysis The final strucutral analysis results will report the worst offending loadcase It will not discriminate between a transporation loadcase or a launch loadcase it simply reports the worst offender This helps in evaluating what part of the installation process is causeing high unity ratio Page 157 Here are a few views of the launch pre condition Sample Sram ary et Installation Launch From Mid Drit nsi M Trim 2 95 Deg FIGURE 3 Figure 65 Side view of Pre Launch Condition Launen e Pen Mik Oe eas M ae o Deg gt lt A I iit i Sg A Fi iW f F Co a See See i ud j SAAN HAS S25 FIGURE 4 Figure 66 Bow view of Pre Launch Condition For the launch portion of the cif file all we need is the INST_LAUNCH command and some of the options For the launch we are doing here we will be setting some of the same v
76. ark definition starts with the comment draft marks In real life vessels have vertical lines painted with numbers so that the draft can be easily read We are going to make several lines perpendicular to the xy plane MOSES will use these lines to report the draft at that location of the vessel In the file we have put a total of four draft marks Two draft marks at the bow and two at the stern two on the port side and two on the starboard side The first step is to make the nodes We have employed a naming convention the first character is b for bow s for stern The second character is s for starboard p for port and the third character b for bottom and t for top Making a total of eight points for four lines Following this convention the point bsb is a point located on the bow starboard bottom To actually define the draft mark lines we use the amp describe body command again Please keep in mind that you need to first define the body then define the nodes to use for the draft marks then use the amp describe body again to further add to the body description Here we use the dmark option Please notice that each draft mark requires its own dmark For the dmark option we need to name a bottom node and a top node Again we 6699 have employed a simple naming convention The first character is b for bow or s Page 58 for stern and the second character is s for sta
77. artment designation Page 21 After inmodel Figure 8 Default view with valve locations After inmodel Figure 9 Compartments with valve locations This gets us the comment that reads Filling up C1 with sounding 2 2m We have seen some of the commands in this section The title is set with amp title Draft 2 2m Page 22 Then the condition is changed with amp instate tests locate 0 0 2 2 0 0 0 The condition will be stored as event 2 And we use our checkloc macro In the log file we find KK KK KK K k k OK K k K KK alarm c1 TRUE xC1 5 10 0 2000001 2K KK k k k k k k k K k k Kk alarm c2 FALSE xC2 10 10 0 7999998 2K OK k k k k k k k k K k K kk alarm c3 FALSE xC3 15 10 2 8 We see that the z values of the locations has changed This makes sense since we changed the draft with the amp instate locate command Since the valve in com partment C1 was opened we need to check how much water is now in the com partment We need to review the results of the amp status commands E n i log00001 txt C test open_valve static_open ans GVIM Oo EEE File Edit Tools Syntax Buffers Window Help GQB2EBBSI 9E saealBRaALSSAlLPGBZal7Aa gt amp status b_w BUOYANCY AND WEIGHT FOR TEST Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified Results Are Reported In Body System Draft 2 26 Roll Angle 6 66 Pitch Angle 6 66 Wet
78. at we are back in the Main Menu our objective is to set the system in static equilibrium in preparation for the dynamic analyses The first thing we want to do in the main menu is check the configuration We do this with a series of amp status commands amp status config amp status cl_flex amp status g_connector amp status tip hook amp status b_w The results of these commands are shown in the log file The config report Figure 45 will show us the position and any forces in each body When you first review the resulting table you will notice that the body ZZZGLOBAXES is listed and that all the values are zero Since we are interested in the values associated with the barge and jacket we can see from the results that the resultant forces and moments N Force are actually quite large Our system is not in equilibrium Page 105 Proc JACKET 222GL0 og00001 bet C test side_lift 2alt ans GVIM File Edit Tools Syntax Buffers Window Help ABBS ae x gt amp status config AG BARRISSA THA7A CURRENT SYSTEM CONFIGURATION ess is DEFAULT Units Are Degrees Feet and Kips Unless Specified Location and Net Force at Body Origin Location 6 66 6 66 20 00 6 66 6 66 6 66 N Force 6 66 6 66 168314 32 43727 27078579 6 Location 143 66 266 66 1 66 6 66 9 08 6 66 N Force 175 16 9 95 1176 29 591 168653 1667 BA Location 6 66 6 66 6 66 6 66 6 00 6 66 N Force 6
79. barge usually along the horizontal level in line with the first node Y is the distance from the centerline of the barge to the first node positive towards starboard Note that if one specifies starboard nodes and a negative Y then the jacket will be placed under the barge rE pke Dn julieb FIGURE 2 Figure 56 Side view of transportation Notice we are using a negative sign and a port side node This means our jacket will be on top of the barge The command to place the barge in install dat should read Page 142 something similar to er e G bn julieb FIGURE 3 Figure 57 Bow view of transportation PaO RK barge data use_ves julieb Pea OA e k k k kkk kkk kk structure data amp SET port_nod J0101 J0201 J0301 J0401 amp SET stbd_nod J0105 J0205 J0305 J0405 oka oo o k k kk kkk kkk define jacket model_in tripod tripod dat 15 17 5 1 5 port_nod stbd_nod orient j0101 j0401 j0105 PaO KOKO oH jacket barge conn tiedown tube 140 25 vcan tube 320 30 i_connector v_can vcan port_nod stbd_nod i connector 4 tie tiedown port nod stbd nod For the command file all we need to do is add amp set d_type 3ddif before the inmodel Page 143 command This will take care of the 3d diffraction project specification Disscusion Command Fi
80. beam along the centerline Our intention is to compare the results to the results we will calculate with the traditional naval architecture method We therefore need to make a structural model with at least the same number of elements as the number of stations used in the plane command The structural model is shown here as a loop The loop begins with the command amp loop and ends with the command amp endloop Before the loop we have to initialize the list variable The two other variables num beams and dist need to multiply out to the length of the barge If there are going to be 80 beams then we need to make them 5 meters in length Meaning we cannot change num_beams without changing dist Now back to the loop Basically the loop makes the nodes then places a beam element between each set of two nodes Towards the bottom of the loop there is a section where the weight per foot 16070425 of the element is defined Let s examine each command The opening of the loop command reads amp loop 111 1 amp number real num_beams 1 1 The format of the command is amp loop INDEX BEGVAL ENDVAL INCREMENT In this case the IIl is the index 1 is the beginning value 81 is the ending value and the increment is 1 Notice that the math 80 1 is done as part of the reading We need 81 elements because there are 80 elements that means that the last element connects node 80 to 81 The first variable is kkk
81. complete list of special characters can be found at http bentley ultramarine com hdesk ref_man cmd_menu htm Next we ask for a report of the categories with amp status cat If we look at the out file we see that there are five categories that have been defined There are the three Page 10 weights we saw in the DAT file and the barge comes with two categories of its own FUEL and L_SHIP L_SHIP stands for lightship hyst lele jme TA out00001 txt C ultraihdesk runs samples hystat fs mom ans GIMI E File Edit Tools Syntax Buffers Window Help aupa el saa BRA SSAl PTBA7AR IE FE JE JE FE FE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE HHH a xxx MOSES HHH MO eee sesressss 19 February 2013 first HHH JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE IE JE JE JE JE JE JE E JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE JE E IE JE JE JE JE JE JE JE JE JEJEJEJE CATEGORY STATUS FOR PART SMITS Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified Results fre Repor
82. de the CIF log and out files Dynamic Frequency Domain Analysis Discussion We are going to discuss the two types of frequency domain analyses here Notice that the frequency domain has its own menu freq_response Both the linear frequency domain analysis and the spectral frequency domain analysis are done within this menu Let s talk about the Frequency Domain There is also a discussion on the website at http bentley ultramarine com hdesk runs c_htm frq_com htm It is important that you understand the difference between the linear frequency do main analysis and the spectral response analysis We are not going to discuss the theory differences between these two methods If you would like more discussion on the differences please read the discussion at the following link http bentley ultramarine com hdesk ref_man freq_rsp htm RAO For both the linear frequency domain and the spectral response analysis we perform the following steps e calculate the response e summarize some of the calculations e report the frequency response e report the motion statistics at a point e report the connector force statistics The main difference is that for the linear frequency response we use the command RAO and for the spectral response we use the command sresponse with many more periods In both instances fr is used to report the frequency response So fr stands for Page 88 frequency response In both instances st_ is used
83. dom There is no checking to make sure the location of the mass is within the defined barge body This command was also part of the p_m files Page 48 discussed as the first part of this exercise Now we check that the system is indeed in equilibrium with the command amp equi is used The results of amp equi show that the net forces and moments are 0 This is also confirmed with the results of the amp status force command Here the results show the inertia and the total rows having values near zero The next set of commands are there to further satisfy our engineering need to show the details of the analysis Also for many projects the input values are part of the report Knowing how to get MOSES to report the input values as part of the output will help in validating the results amp status b_w reports the status of the buoyancy and weight of the body amp status cat is short for amp status category Recall that in the dat file the weight distribution we assigned to each beam structural element was labeled as elat When we look at the Category Status For Part Barge report we see the structural beams weigh 4 821E6 mtons labeled as ELAT and the weight added 6762 mtons labeled as amp DEFWT When the amp weight compute command is used the default is to label the category as SDEFWT In the next section we also report more details on the model via the summary menu This menu is entered with the command amp summary and ends with t
84. e following picture you see the point selection J4003 J4001 J8003 J8001 will result in the desired coordinate system Figure 3 shows the locations of the points test of damaged leg during flotation Event 1 2 38001 IZ Y ns lt e IES aw SN 044 WA SNS Figure 28 Points used to redefine the part coordinate system The commands used to create the picture are amp select ppp select j4003 j4001 j8001 j8003 amp picture top render gl water no points ppp anotate points The only thing you will need to do with the mouse is set the event to 1 with the Page 64 slider bar and use the up and down arrow keys to zoom in or out as desired This is all we need to do as far as editing the model In the next set of commands we get a summary report of the compartments defined in the data file We have seen the amp summary menu earlier when we discussed the allowable KG macros Here we are asking for a compartment report instead of a category report As you can see the amp summary menu is a prepared way of presenting summaries of the database Following that we use the amp status command to get the status of the compartments We have seen the amp status many times in the other exercises In the next set of commands we find the initial floating position This is the first time we see the guess option used on the amp instate command The pair of commands amp instate and amp equi are needed to find the e
85. e location of the weights is set with the points wg1 wg2 and wg3 Notice that we specified which units we are using with the amp dimen statement It is always a good idea to specify the units at the top of the file Let s look at the dimension statements in the CIF and the DAT file This analysis will start using meters and m tons The command in the DAT file tells MOSES to e Save the current dimensions save then e Accept all future input as feet and kips dimen feet kips The last command in the DAT file amp dimen remember tells MOSES to return to the previous saved dimensions All of this might seem elementary but by using the save and remember options many errors due to units can be avoided For this exercise we will discuss the CIF file and the output it produces at the same time It would be a good idea to run the analysis and have the log and output file available The CIF file has many of the commands that we have seen before The condition is set by amp instate then some ballast water is put in the compartments with amp compartment Then we make a selector named tow to pick six compartments for MOSES to work with Notice that two of the compartments we chose for MOSES to work with are also compartments that we have placed water in A selector name begins with the colon character Just as in any language there are special characters in MOSES In MOSES the colon is a special character The
86. e A 1 2 0 901 800 57 kips Exercise B 1 2 3 4 Fails minimum GM 2037 KN 68 99 KN Exercise C The answers for these questions may differ from those presented here The answers are dependent on the ballast arrangement These answers were determined with the ballast arrangement Na 4P 4S 5C 5P 5S me Full 96 13 73 5 53 4 100 64 82 Answers 1 2 7 1 6 90 KN 4 11 KN Yes L6796KN 0 072 0 165 0 299 0 Translating from SACS Exercise Exercise A 1 2 215 kN x 0 m y 13 79 m z 45 91 m Page 164 3 48328 kN Exercise B 1 x 11 26 ft y 130 13 ft z 13 10 ft 2 1553 kips 7 11 Longitudinal Strength Exercise Exercise A The command amp equi moves all six degrees of freedom The command equi_h move only z rx and ry Exercise B The shear force and bending moment have small changes compared to the original results Exercise C 63 32 kips ft Exercise D The shear force and bending moment from weight distribution in exercise C more closely resembles that in the original set up using amp weight compute 7 12 Modeling a Fender Copy the fender cif command to another root name for this exercise I will use f_exer cif Insert the line amp device auxin fender dat before the inmodel command so that you can use the same data file fender dat Change the amp instate locate command for the barge to the following LOCATE barge 171 29 35
87. e Introduction to Linear Frequency Analysis e Introduction to Spectral Frequency Analysis e Introduction to Time Domain Analysis e Demonstrate some graphic interactive features Reference files mp_moor cif mp_moor dat Modeling Discussion For a general discussion of mooring analyses performed with MOSES please see http bentley ultramarine com hdesk runs samples mooring doc htm This file shows many MOSES capabilities This file is also discussed in detail on the website http bentley ultramarine com hdesk runs samples mooring mp_moor htm The workbook is a complement to the material presented on the website it is not a substitute The material presented on the website covers the same file but there are different aspects presented here First we discuss the modeling In the next exercise we discuss the commands to perform a dynamic analysis The reference files are in the samples directory under mooring The reader should be familiar enough with the web page to be able to locate these files and place them in the directory they will be using We will start by discussing the DAT file since it is rather short The first new options we see are the cs_wind and the cs_curr being used with the command pgen The reader should be familiar enough with the manual to find the manual page corresponding to pgen Basically we are telling MOSES to compute the exposed wind and current area and then compute the force based on wind and
88. e have to declare a name for the current environment This is a still water analysis meaning there are no environmental forces The command amp env none makes an environment labeled none with zero environmental forces With an environment declared we can now perform a structural analysis The structural analysis menu is entered with the command struct and is exited with the command end Inside the structural analysis menu we first create a load case based on the current status condition with the environment associated with none This is done with the command Icase static none The structural solution is solved Page 50 for with the command ssolve Inside the structural analysis menu the solved solution is calculated We have to go into the structural post processing menu to report the values or to further manipulate them As part of the structural post processing we will be making the comparison of the traditional method to the structural analysis method Before we start structural post processing we need to further process the data we collected earlier First there is sign change to be made In traditional naval architecture bending moment is positive for a sag case In structural analysis the bending moment is negative for a sag case The two sections with loops set off by the the comment change sign of traditional results to match coordinate system of structural analysis is where the signs are changed Before the loops are
89. e in the workbook since the commands in the CIF file can be explained by following the web page discussion on rao cif Generating the hydrodynamic database is one part of the analysis that can take much computer time Strip theory in general is faster than 3D Diffraction The greater the number of panels used to define a diffraction mesh the greater the computer time needed to generate a hydrodynamic database In the frequency response menu most of the commands begin with the fr or st characters The commands that begin with fr compute frequency responses and the commands that begin with st compute the statistics What comes after the underscore tells MOSES what quantity we are looking for Here we used point Page 69 when we are interested in the frequency response at a point Please note that there is always an fr command the responses have to be computed first before any statistics can be computed and reported Exercise A Change the file cargo dat so that line 11 reads pgen cargo perm O cs cur 1 1 1 cswin 1 1 0 Compare the changes in righting arm results this change causes If you look up the pgen command in the manual do the changes make sense Exercise B The project has informed you that the transportation will now have two pieces of cargo Leave the current cargo where it is and add the second one with the following information e The dimensions of the cargo length 50 ft width 6
90. e local body system For this barge the origin of the body system is at the intersection of the bow centerline and keel The forces show that there is a net positive force in the z direction and a net negative moment about the y axis This stands to reason We have only defined a weight for the structural beam model of the barge The positive z direction force tells us that the buoyancy force is larger than the weight force The buoyancy force is probably located near amidships This would create a negative moment about the body y axis When we review the results of the command amp status force our above reasoning is validated We see that the inertia force is 6763 mtons This means that in order for the sum of the forces in the z direction to equal zero a force equal to 6763 mtons would need to be added or a weight of 6763 mtons would need to be added Please be careful in interpreting the values in the Inertia row These values represent the inertia needed to put the system in equilibrium When the system is very near equilibrium the values in the Inertia and Total rows will be small Up to this point we have established that we are not in equilibrium The command amp weight compute bname zcg kx ky kz will get us in equilibrium A word of caution is warranted here MOSES will place a weight on the xy plane where z zcg This weight will make the XF 0 for all three degrees of freedom and XM 0 for all three degrees of free
91. e offset due to the bracing needing to join the chord at the outer diameter The distance from the node to the chord outer diameter would be taken out from the computer model with the offset option When the models are read in their part coordinate systems are coincidental What we want is for the jacket to be placed somewhere on the barge deck After the inmodel command we place the jacket origin within the barge coordinate system This is done with the command amp describe part jacket move 200 0 25 0 0 0 Remember that the joint db0 was defined at the jacket origin The amp describe command will put point db0 at x 200 y 0 z 25 without any rotations The jacket part x y and z axes are still parallel to the barge body x y and z axes In the next command amp instate locate tow_brg 0 0 10 000 0 0 we are placing the barge body tow_brg body which includes the tow_brg part and jacket part system Page 123 so that the barge coordinate system is negative 10 ft in the z direction of the global coordinate system More simply stated the barge is being put at a 10 ft draft So far we have just moved the jacket with respect to the barge We have not established any connections between them The vertical supports cans and the sea fastenings tiedowns are defined in the next set of commands All of the cans and tiedowns are referred to collectively as part connectors and are defined within the model edit medit menu For bot
92. e the compartment is the same as inside the compartmnet H T 10g00001 txt C test open_valve static_open ans GVIM File Edit Tools Syntax Buffers Window Help anmala e Zan BARA ASALTA A Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified Results Are Reported In Body System Draft 3 66 Roll Angle 6 66 Pitch Angle 88 Wet Radii Of Gyration About CG 4 47 K Y 5 65 K Z 5 27 Center of Gravity Sounding Full Weight X v Part TEST LOAD_GRO Contents 1009 45 Buoyancy 615 63 Figure 15 Buoyancy and Weight Report for Event 4 Page 27 fb togoooot testopenvhc taucopenars cvIM iT File Edit Tools Syntax Buffers Window Help ABBS ONG XSG BRASSA THA7A gt amp status compartment a COMPARTMENT PROPERTIES Results Are Reported In Body System Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified Fill Specific Ballast Full Sounding Name Type Gravity Maximum Current Max Min Curr c1 U_OPEN 1 6256 356 6 175 6 166 68 6 66 56 65 3 663 c2 U_OPEN 1 6256 175 3 87 8 166 60 6 66 56 65 3 663 c3 U_OPEN 1 60256 175 3 146 6 166 606 6 66 83 35 5 661 HOLE DATA Results Are Reported In Body System Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified Hole Location Normal Friction frea Name
93. ea under the wind heeling moment curve to the second intercept 3 Area under the righting arm curve up to the angle of maximum righting arm equal to or greater than 15 foot degrees Table 2 Stability Criteria as it Appears in the CFR The following is how they map to the options presented in the stab_ok 1 The GM must be greater then IGM or DGM IGM gt 0 083 The area under the righting moment curve will at IRATIO gt 1 4 tain a ratio with the area under the wind heeling moment curve of at least IRATIO or DRATIO with both measured at the lesser of the downflood ing angle or second intercept 3 The area under the righting moment curve up to IARE MARM gt 15 the angle where the righting arm is maximum is at least IAREQ MARM or DAREQMARM ft degree or m degrees Table 3 Stability Criteria and Option Variable Questions Check the three criteria above for both the intact and damage stability Check these for a draft of 7 ft 1 Check intact stability for 100 knot wind pass fail 2 Check damage stability for 50 knot wind damage compartment 5P pass fail Page 36 M_STAB Discussion KG_ALLOW The documentation of the Allowable KG command is at the same location as STAB_OK The last part of m_stab cif file finds the allowable KG We have to be careful about what center is being referred to If you review the log file you will see that MOSES iterated many times and r
94. em without tiedowns was solved for the still water case loadout Then the system with tiedowns included was solved for the other load cases The still water load case was combined with the other cases in the post processor so that the effect of the tiedowns is felt only under dynamic loads A separate section of the program output is dedicated to the tiedowns Here beam internal loads and code checks for only the tiedowns are shown The beam loads have been condensed into an envelope In other Page 137 words each value presented is the maximum overall load case The load cases used for checking the tiedowns are simply the dynamic loads mul tiplied by two This assumes that no tension connection is developed between the tiedown brace and the barge deck and that the tiedowns are arranged as inboard outboard pairs In this manner tension that would have been developed in the tiedowns on one side of a support is added to the compression in the tiedowns on the opposite side Vertical support was provided by support cans attached between the cargo and the barge deck These supports were modeled as beams and their loads are shown in the accompanying MOSES output in the reports titled BEAM LOADS and BEAM ENVELOPE The first of these gives the still water loads and the second gives the minimum and maxi mum overall load cases Since these are beam loads the vertical support load is the axial load in the beam and follows the standard c
95. en you change the ballast arrangement during a process All of these commands get us to the disposition menu There are standard reports for all of the sub menu categories Here we ask for the standard report of all of them with the command report We ask for plots of the trajectories and the tank ballasting with the command plot Remember we can use the vlist command to determine what numbers to use with the plot command These two plots along with some bow views of the events follows Test of Dynamic Compartment Flooding sinking L 2 i i f 9 g j ji 03 14 4 r 4 2 29 Z TBRG 105 88 RyibRe 6 T T T T T T T T T x 0 47 94 141 188 235 282 329 376 423 470 Event Figure 25 Z and RY motion of the Body Origin Page 61 Test of Dynamic Compartment Flooding sinking ONE F ull 188 235 Event Number Figure 26 Compartment flooding in percentage Figure 27 Events during flooding Page 62 Up_damage Dat File Discussion The file can be divided into the four sections e definition of the classes all begin with the character e definition of the beams all begin with the word BEAM e definition of the joints all begin with the character e definition of the compartment section at the bottom with many occurences of the amp describe command The first three sections are needed to describe a jacket The format is similar to that which one would get after translatin
96. enerates the table Launch Way Geometry that is found in the log file When you review this file you will see many of the inputs that were used in the This is a good place to do Exercise A Performing the Launch The next command actually performs the launch LAUNCH MAXTIM 100 MAXOSC 5 TSTEP 5 25 5 WINCH 5 This command performs the launch simulation The log file contains a small summary of the analysis it is titled Launch Events Summary The options used are presented in the order that they are used in the simulation The option WINCH tells moses to assume the winches can move the jacket 5 m sec until the jacket starts sliding The log file shows that sliding occured at 0 5 seconds Tip occus at 30 seconds and Page 150 separation occurs at 37 25 seconds The oscillations are at 54 25 60 25 66 25 and 72 75 seconds The simulations ends at 72 5 seconds because this is the 4th oscillation and the option MAXOSC told MOSES to stop before 5 The option MAX TIME which designates the final simulation times was not used Had the oscillations taken longer to occur the maxtime may have been reached In the log file the table Launch Events Summary has columns Time and Change in Time which seem to report at various intervals but not what is designated in the TSTEP option To see the effects of th TSTEP option we need to go to the output file The report Location of the Origin of Selected Bodies was
97. ent of the selected part s is submerged between el and e2 The result is the list of pairs where the part enters and exits the water The value 0 is part of the first pair therefore it gets reported Now we get back to the project requirements for the structural analysis we are to use the forces at event 5 and the second occurrence of a slam event We are going to interpret this as the second event reported by the amp slam command We want MOSES to do this automatically for us During a project many things can change and we certainly do not want to be running a lengthy time domain analysis then half post processing the results to get the event at the second slam and then restarting MOSES to finish post processing Gathering the list of slam events is considered post processing however it is done in the Main Menu For the rest of the post processing of the the domain we will be doing it in the Post Processing Menu This is where we can use variables and the string function amp token First we set the variable f_time to the string of times resulting from the amp slam command Then we use the amp token command to pick the second value At the end the variable f_time will be set to 20 2 Now we are ready for post processing The majority of the post processing will be done inside the Post Processing Menu which is entered with the command prcpost What I mean by post processing is somehow getting MOSES to only display the values in t
98. eports the allowable KG to be 20 93 If you review the out file you see that the subtitle reads VCG 20 93 ft and the table header reads KG 15 61 There seems to be some confusion here What is being referenced with VCG and what is being referenced with KG Add the following before and after the kg allow command amp status categ both Now when you re run that analysis there will be two more Category Summary for Selected Parts reports in the output as shown below E Ei out00001 txt C test samples hystat m_stab ans GVIM1 File Edit Tools Syntax Buffers Window Help ABBS Se X Se BRA SSA TAa A PARTS Process is DEFAULT Units Are Degrees Feet and Kips Unless Specified Results Are Reported In The Part System Weight Buoyancy Center of Gravity Category Factor Factor Weight Buoyancy amp DEFWT 1 666 2866 28 L_SHIP 1 668 945 18 TOTAL 3751 38 Figure 19 Results Before the KG_ALLOW command Page 37 File Edit Tools Syntax Buffers Window Help AEBSAeE s SS BAR SSAITHA72A CATEGORY STATUS FOR SELECTED PARTS Process is DEFAULT Units Are Degrees Feet and Kips Unless Specified Results Are Reported In The Part System Weight Buoyancy Center of Gravity Category Factor Factor Weight x Y rs Buoyancy amp DEF WT 1 666 1 606 1699 56 161 69 8 88 26 93 6 66 L_SHIP 1 666 1 666 945 18 96 66 6 668 6 99 6 66 TOTAL 2644 68 97 13 8 88 15 95
99. escribe part cargo simply tells MOSES that we are going to describe a part and that MOSES should classify it appropriately A body can have many parts and each part can have its own name Parts with the same name as the body are referred to as body parts It is the intent to show through example how to use body parts and how to use regular parts The part that we are going to describe will have a weight and a piece associated with it The weight is used to define the mass matrix and the piece is used to define the wind and current areas to attract wind and current loads respectively It is not necessary to define the wind and current areas in this manner As an example we Page 68 are showing how to define the wind and current areas by employing a piece Let s discuss the commands weight pgen plane and end_pgen The first item is defining the point car_cg We need to somehow describe the geometry of our items cargo to MOSES We describe the geometry by a set of points Then we tell MOSES what we want at the points or if we want to join the points to make a surface Here we are describing the point where the center of gravity of the cargo will be We define the weight of the cargo with the command weight It is assumed that by this point the student can look up the command format for weight in the online manual To define the cargo we need the mass properties and the geometry description The geometry description i
100. ession of connectors and bodies The first set of files shows one set of connectors between a hook ground body and a jacket body The second set of files show two sets of connectors between two separate hooks and one tripod jacket body The third set of files shows one set of connectors between a hook and a spreader bar a second set of connectors between the spreader bar and a deck then separately a third set of connectors between a hook and the deck File Name Analysis No No Bodies Tip Hook up_lower Lower 1 1 Upend 1 1 two_blk Lower 1 1 Upend 1 2 spread Lift 2 2 Table 4 Pregessive Complexity of Exercise For both the up_lower and the two_blk analysis two processes are defined One process for the lowering and one process for the upending These files also show how to activate connectors when in use and deactivate connectors when not in use Discussion Single Tip Hook Assembly This set of files shows how to define a single tip hook assembly The discussion for up_lowr cif are located at http bentley ultramarine com hdesk runs samples install up_lowr htm Page 73 Jacket Lower Upend Analysis Events 0 0 14 0 Figure 29 Side view of 4 pile jacket during lowering process Figure 30 Isometric view of 4 pile jacket during lowering process Page 74 Jacket Powertipend Analysis Events 0 0 37 0 Figure 31 Upending with a single Tip Hook Assembly Discussion Tip Hook Assembly Usin
101. frequency domain analysis we had sub menus to report the results Here there is a menu for post processing of processes with events Since the time domain is essentially a collection of events we will use the PRCPOST menu We are going to report all of the results within sub menus of the PRCPOST menu There are similarities to what we had done before We will have to issue a REPORT command to get the standard report within the Disposition Menu and we will have to end out of the Disposition Menu For the points disposition we have 133 variables The number of variables here will really depend on how many points you are interested in For the command points it would be best to always ask for the variable list vlist then choose the variables you are interested in reporting then rerun the analysis For an analysis with more bodies or more mooring lines you may want to first run the time domain for 10 seconds and get your variables then run for the proper length of time and then review your Page 89 output Depending on the number of bodies in your analysis you may want to do this for all commands in the PRCPOST menu There is a new command in the disposition menus under the PRCPOST menu In the frequency domain disposition menus there were the commands that began with the characters ST to report the statistics In the PostProcess menu we have the command STATISTICS It is because the number of available variables can change w
102. ft blank An acceptable input for s_desired has to be a numeric value when MOSES reads a word as the third entry it knows that s_desired is not being set Instead it sees that the word value is an acceptable input for s val For the second option limits it is easy to see the lower limit is 0 1 and the upper limit is 100 This means that any time the third value of the point location is between 0 01 and 100 the sensor value will be false This section is repeasted for compartment C2 and C3 Then a selector is defined amp select hole select C1 C2 C3 Selectors are a means to group a set of entities Here we are anticipating needing information about the three points It will be much easier to ask for the information for the group with the hole name instead of typing out all three points In the next section we define a macro Macros are used to create new commands There are many analysis where several configurations are examined and the same set of data is reported If a command that creates the desired output is used this saves us from human error The command that we will be creating is checkloc The purpose of this macro is do three things 1 to report the valve z location 3rd value of the point location 2 report the value of the sensor and 3 if the sensor is true open the valve The same sequence is done three times with a name change We are going to review Page 18 line by line only for one se
103. g Two Separate Hooks This set of files shows how to use a sling assembly to lower a jacket into the water Then a new sling assembly is defined and used for upending A similar analysis is done in the two_blk files found at http bentley ultramarine com hdesk runs samples install two_blk htm Here a single hook and assembly set is used to analyse the lowering of a tripod into the water The second processes uses two hooks to upend the tripod Page 75 Two Block Upend Analysis Event 4 00 a aw Coates ae Ree lt 3 ZL So eS SIZ OS V A eh Figure 32 Side view of tripod jacket during lowering process Figure 33 Isometric view of tripod jacket during lowering process Page 76 Two Block Upend Analysis Rotating Stage Angle 19 18 vent 2 00 Figure 34 Upending with a Two Hook Assemblies Discussion Tip Hook Assembly Using Two Separate Hooks and a Spreader Bar Finally the spread files show how to define a spreader bar for use in lifts The list and trim is because center of gravity is not a tthe gemoetric center The results of the command amp status b_w also show this Page 77 Figure 35 Front view of deck lift HYN Figure 36 Side view of deck lift Page 78 Exercise A up_lowr files Does the restraint report for event 1 of the lowering process agree with the connector force magnitude report Exercise B up_lowr files 6 The environment description inculdes the
104. g a model from SACS format In general a jacket model is used when structural detail is needed Structural detail is a very broad term and can include anything from weight distribution to joint can definition For our analysis it is sufficient that the jacket model has structural members that have weight and buoyancy attributes When MOSES reads a data file it takes it awhile to process all of the information Notice that the BEAM definition which uses the joint definition is before the joint x commands It is acceptable for the definitions to be out of order in the data file MOSES takes the information sorts it then puts it together The compartment definitions are found towards the bottom of the file The format is very similar to what we found in sink dat This is the first time we are going to use the tubtank command to describe a compartment We are using the command tubtank to model the compartment defined by the interior of the jacket legs The jacket legs can be described as long cylinders The command tubtank is an easy and computationally efficient way to describe compartments that are cylindrically shaped Notice that the compartments are described in SI units whereas the rest of the jacket is described in feet and kips The use of the amp dimen command with the options save and remember make the use of mixed units easy to handle Up_damage Command File Discussion Reading the model with the inmodel command gets us to the model
105. g the stiffness in x y z and rx for spr2 For the structural solution just one restraint in roll is needed for a solution to be found The restraints are connected to the first node and the last node In both cases the nodes are connected to the barge structural model at one end and to ground at the other end This is all the model editing we have to do It is a good idea to wait and model the restraints in the command file This way the model can be placed at the desired orientation in our case the proper draft roll and trim before any connectors to ground are added A picture is generated with the amp picture iso command There really is no good or bad reason to place this command here It is always a good idea to provide a picture of your system The author of the command file simply chose this as the place In the next set of commands we review the status up to this point then we alter the mass properties such that the system will be at equilibrium for this condition This is in the lines that are set off with the comment compute weight In this section we are going to also be discussing the values in the log file It would be a good idea to run the analysis and have the log and out file available in the answers ans directory The first command amp status config reports the status of the configuration It summa rizes the location and the net force The results show that the barge is at 12 m draft The forces are reported in th
106. g to include wind and have used a 0 to indicate this The last two options draft dd trim tt tell MOSES which draft and trim to use We want to make sure we are using the same values as the native command files 10 and 0 That is all of the changes that are needed to the installation tool files The tools take care of all of the stability hydrodynamics and making load cases for us Review the answers directory At this point we have discussed the approach to the native command method and the installation tools method Some of the log and output file for the native command method was discussed when the native command file was discussed We are going to be mostly reviewing the results of the installation tools method with some comparison to the results from the native commands method When we review the results in the answers directory the first thing we notice is that the native commands produced 9 graphic files and the tools produced 22 graphic files The first five graphics are the same The first four are shown as Figures 5 to 9 in this workbook The fifth one is the results of the stability analysis They are four views of the system and the results of the stability analysis For the tools results the RAOs are presented in graphical form in graphic files 6 to 13 and in tabular form pages 25 to 32 of the out file In the native command results only the tabular form of the RAO was produced in pages 18 to 20 Remember in the native command
107. ght horizontal lines Next we plot the magnitude of the boom and the slings For this plot we will definitely see some changes as the events change Note that for both plots the main title subtitle and axes labels are defined If this is not desired say you are doing a quick check plot then this could be omitted and the option no_edit used The no_edit option tells MOSES to use the default labels Once we have created the plots we ask for the standard reports with the command report then exit the Disposition Menu with end Now we are back in the Post Processing Menu The plot of the connector magnitudes shows that the sling tensions right hand axis can change from 70 to 640 kips We can compare the maximum number to the 629 kips reported via the linear analysis Reviewing the frequency domain report headers we see that the 629 kips is mean plus maximum We know from our static analysis that the mean value for sling is 339 kips This means that the dynamic portion is 290 kips 629 339 290 For a linear analysis the dynamic portion is added and subtracted which results in a minimum tension for sling of 49 kips 339 290 49 Just comparing linear and non linear analyses for the the maximum and minimum sling1 tension values leads us to believe a linear analysis is not too bad Next we compare the motion results We do a similar set of commands for the trajectory menu We get the association of the numbers with the colu
108. h Angle 8 00 Wet Radii Of Gyration About CG M K xX 6 16 K 18 62 K Z 19 12 GHT 12 86 GML 155 76 Center of Gravity Sounding Full Name Weight a a a ccesccse cesstadn Feat lea etait Part SMITS SSS5S Sa55 LOAD_GRO 7706 60 46 08 6 66 4 32 Contents APSS 254 09 5 59 10 29 4 00 6 16 166 66 ASBS 254 69 5 59 10 29 4 60 6 16 166 66 3PSC 747 28 40 00 3 43 2 60 5 21 85 46 3SBC 747 28 40 00 3 43 2 60 5 21 85 46 SPSS 745 06 81 15 18 29 2 60 5 20 85 36 SSBS 745 06 81 15 10 29 2 60 5 20 85 36 Total 11199 48 48 18 6 66 3 85 Buoyancy 11199 47 48 168 0 00 2 34 X 209 1 22 Figure 5 Results of amp status b w with type app none Let s concentrate on the GM change between the second to the third case If you remember from your naval architecture class free surface in the compartments re duces the metacentric height What is being shown here is that the third set in which Page 13 we specified the compartments to with a fill type of APP_NONE do not have a free surface moment correction Let s look briefly at the commands towards the end of the file We have used the cform command before to generate the curves of form The curves of form include the displacement and the distance from the keel to the metacenter KM Note that the curves of form are based strictly on the hull geometry Also toward the end of the command file we have tank_capacity This command generates the tables tit
109. h cans and tiedowns we will be using tubulars of outer diameter 20 inches and 1 in thickness We have defined two classes vert and tiedown to make labeling easier The definition of the vertical support cans connectors begins with the command amp describe part can pconnect It is important that pconnect is included in this command For the vertical connectors we have conveniently left points on both parts that line up vertically to connect Each of the four vertical cans is defined separately with the command pconnect Basically we are telling MOSES to start with the jacket point and move in the negative z direction to find the corresponding point on the barge Please note that for the can definition we were explicit about which node on the jacket and which node on the barge to connect At this point we compute a weight can be positive or negative needed for the body system to be in equilibrium We confirm this weight calculation with the amp equi command Then we define this setup as event 1 This will be the setup used for the still water case later This is meant to represent the project after loadout but before the tiedowns have been welded The definition of the sea fastenings tiedown connectors begins with the command amp describe part tiedown pconnect Again it is important that pconnect is included in this command We will be defining four tiedowns at each corner of the jacket The tiedowns will ha
110. h defining the weight weight the added mass amass and the drag drag attributes For the extended list of attributes please see the following link http bentley ultramarine com hdesk ref_man load_g htm ELAT The displacement of the body buoy is defined by a tubular beam element Two nodes one at the top bb and one at the bottom bt are defined The command format is the same as the structural model used for the long_str barge beam model however different values are used for the options That concludes the definition of the buoy body The barge model is similar to the other vessels we have seen The attribute tanker is new and the use of the cartesian coordinate system is new The documentation for the attribute tanker is at the same location as the attributes used in the buoy model Basically the option cart is followed by y z pairs The documentation for Page 93 the cart option can be found at the following link http bentley ultramarine com hdesk ref_man pieces htm That concludes the discussion for the data file Now on to the command file Command file Discussion The top of the command files begins as most of the command files have In previous analysis we have edited the model inside the model edit menu medit For this analysis we need to be careful and make sure that any model editing is done on the body we specify This is why there are two amp describe body commands within the model editing menu For the
111. hat the tiedown orientation is as input through the use of the member y direction cosine matrix For the beam ends report we are given the location of each end of the tiedown in the barge part coordinate system Please note that we are paying special attention to the part system designation for these reports We want to be careful and provide Page 126 proper documentation BEAN Process is DEFAULT Units Are Degrees Element Class Node Releases Name Hane Name FX FY FZ WX MY MZ x TIED 617 TIEDOWN DB1 6 U1 48 TIED 618 TIEDOWN DB1 6 2U1 48 TIED 619 TIEDOWN DB1 6 U1 48 TIED 020 TIEDOWN DB1 8 aU1 48 TIED 021 TIEDOWN DB2 6 U2 48 TIED 622 TIEDOWN DB2 6 22 48 TIED 623 TIEDOWN DB2 6 22 48 TIED 024 TIEDOWN DB2 6 U2 48 TIED 625 TIEDOWN DB3 6 2U3 48 TIED 626 TIEDOWN DB3 6 48 48 48 PROPERTIES Part Offset in Feet and Kips Unless Specified 7 B1 K L Ref Node Ch Angle 2 Mem Y Dir Cosines 7071 7071 7071 7071 7071 7071 7071 7071 7071 7071 Y 7071 7071 7071 7071 7071 7071 7071 7071 7071 7071 2 Length 6668 7 55 6668 7 55 6666 7 55 6068 7 55 6668 7 55 6666 7 55 6668 7 55 6668 7 55 6668 7 55 6666 7 55 207 1 Weight 1 53 1 53 1 53 1 53 1 53 1 53 1 53 1 53 12 Figure 48 Tiedown Pro
112. he denotes class names When we define the class we will also be defining its properties We are interested in the command on line 48 pardum pri 21000 2 15000 section 4 398e8 5 65e16 7 854e16 9 6304e16 The command can be found at the following link http bentley ultramarine com hdesk ref_man bod_par htm cls_str In the page for class structures we can find the general dimension of a PRI class The values we have used here for the PRI are the gross dimensions of the barge We need to make sure that the same section properties are used for the classical naval architecture method and for the structural analysis method In the structural analysis method we are interested in the JY term because this is used for loading along the barge centerline in the global z direction If we review the documentation for the amp describe body command we see that EI is in terms of bforce m units Since we are in meters and kNts this would be kNts m If we review the element properties documentation we see that for a class definition section A IY IZ J a_y a_z use mm for IY and IZ What we know is that Page 44 IE 113 10 1kNts m 2 7 1 and kNt E 200 10 2 7 2 m therefore 113 10 kNts mm Pei S 56 500m 2 7 3 200 108 kNts Which then gives us I 5 65 10 mm This is the value used for JY in the section option This completes the section properties definition The rest of the structural model is a
113. he tanker is less than 2 05m meaning that the connector is in compression The force should remain at zero when the distance between the barge and the tanker is larger than 2 05m meaning that the connector is in tension Since we have defined our Page 82 GSPR to be a compression element only then it should be turned off for any positive forces For all of these moves we are going to be using the F kx basic equation in the initial position of x 0 The force reported with the amp status f connect command shows that the force in each fender is also zero Every move is done in a set of four lines The results of the four line command are all placed in the log file They are all similar to the first set Therefore only the first set will be discussed in detail amp type amp type connector force barge im towards tanker amp instate move barge 0 1 0 amp status f_connector The first amp type writes a blank line The second amp type command leaves a short message in the log file The purpose of the message is to make the log file easier to read If a group of tables are presented one right after another and the only thing distinguishing them is the values it helps to leave a short message to keep track of why the values are different The amp instate command moves the barge in the global y axis Some of the moves are in the negative direction some of the moves are in the positive direction The last command amp status f connecto
114. he command end This reporting goes to the output file The first set of reports deal with class properties This creates the Class Dimensions Summary Material and Redesign Summary and the Class Section Summary These are pages 3 to 5 of the output When you review them you will see the values we used in the data file to define the structural model The second command in the summary menu is compart_sum long This creates the Vessel Section Properties for Barge report When you review the report you will see values we used in the amp describe body barge section command in the data file In the next section labeled Traditional Long Str the same approach as was presented in the p_m files is taken The Hydrostatics Menu is entered with the hstatic barge command and is exited with the end command The bending moment and shear is computed with the moment command This puts us in the Disposition Menu In the p m files all we did was make the standard report with the command report Here we also generate see Figure 23 with the command plot 1 2 rax t_sub Traditional Results In this set of files we are interested in making a comparison So we have to somehow store the values for later use This is what is done in the lines beginning with the command set Here a variable is being defined but is not exactly like the command amp set The command set is only valid in the disposition menu and serves to store data that is currently a
115. he database that are interest ing to the project During the analysis many items were added to the database To name a few at each time event wave height wave force force on the connectors position of each body and velocity of each body By post processing we are going to get MOSES to display the values the project wants to examine In order to compare the time domain results to the frequency domain results we need to get the motions and the connector forces We first get connector forces with the command conforce This command puts us in the Disposition Menu again Then we ask for the list of variable names or column headings vlist that are available In the log file we see that there are 57 values available the events and 8 values for each connector For now 57 values are not too much to work with If we had needed to keep the list of variables to a more manageable size we could have made a selector to restrict the data to those in which we are interested The format of the command would be conforce sname Page 113 From the results of vlist we that see 1 corresponds to event number 8 corresponds to magnitude of airtugger 1 and 16 corresponds to magnitude of airtugger 2 The command which makes a plot of the three values is textstyleEmphasisplot 1 8 rax 16 t main Airtuggers If you recall when we defined the airtuggers we did not give them the ability to change magnitude So our plot is going to be two strai
116. he default structural analysis performed with the MOSES tools takes out the tiedowns for the still water case makes any mean load cases to include the mean wind force and combines these cases with the dynamic portion For the analysis in the tow_native files a much more limited set of load cases is presented The structural solver menu is used two separate times The first time for the still water case and the second time for the wave environment load cases We use the same procedure for both instances e define the load case with Icase e define the restraints to be used with s_rest will leave blank e define the parts with s_part to be included this changes e finally solve for the structural solution with ssolve For both times through the structural solver we leave the list of restraints to use blank For this analysis we are using a rigid barge The restraints needed to keep the jacket on the barge deck plane are provided by the fact that the barge is rigid We do not need to include any other restraints since we are only performing a structural analysis on the jacket tiedowns and cans We define the still water case the first time through This is meant to represent the stage after loadout has finished but tiedowns have not been welded To do this the list after s_part contains only jacket and can for this load case The option nonlinear is used Many times the connection between the jacket at the cans or tiedow
117. he linear response menu to make sure our setup did not cause problems with the software considered basic checks The sling elements can go slack making them non linear connectors and therefore we should only consider the results of the non linear analysis In the next set of commands we are going to be using the amp buildg menu This is where we combine the three distance columns into one plot Recall that we have created the variables redgel redge2 and redge3 as part of reporting the relative motions These variables have been populated with the string values representing the distance between the two points at each time step The main purpose of presenting the gathering of this data in the amp buildg menu is to show the set of commands to put this new table together MOSES is a programming language and is intended to be able to analyze many different types of configurations MOSES comes with preset formatted tables for the analyses considered common Being able to use the amp buildg menu is a way to gather data and further process it for the uncommon configurations Before entering the Build Graph Menu we need to know how many rows there are going to be We will of course let MOSES figure this out for us Here is another instance where the use of the string command amp token n string comes in handy The string command determines how many tokens or entries are in the variable event and sets the variable n equal to that We will use a
118. i_h Notice that the comments in the CIF file tell us we are entering the hydrostatics menu Once inside the hydrostatics menu we can perform hydrostatic calculations When MOSES is working if you look at the upper blue bar you will notice that the words change from Main Menu to Hydrostatic Menu and Disposition Menu Notice that after each report command there is an end command After each calcu lation MOSES is in the disposition menu When we ask MOSES to report we are asking MOSES to dispose of the results Once we have finished reporting we end that section of the calculations After each of the calculations a plot is generated with the command plot The numbers after the command plot tell MOSES what variables to use as the ordinate and the abscissa We can edit this file and add the command vlist before or after the command plot to get a map of the number to variable used Page 5 Wave at Barge origin x 0 218 Moment 1084 T r 160 200 Long Location Figure 1 Hog case for basic run Wave at Barge amidships x 200 72 108 718 Moment 103 252 288 T T 160 200 Long Location Figure 2 Sag case for basic run Page 6 Exercise A Answer the following questions The answers are found in the directory b_run ans in the out00001 file Questions 1 What is the KML and KMT for a 12 ft draft 2 What is the righting arm at 28 deg roll 3 At what longi
119. ibrium position The values in the Roll and Trim columns are referenced to the initial values For the results where 1s is damaged the righting arm when the vessel is at 2 1 44 0 56 deg roll is 0 35 feet After the stability results are reports summarizing the configuration If you recall these are the results of the amp status command The following associates the command with the table header Page 33 amp status configurre Current System Configuration amp status b_w Buoyancy and Weight for CBRG180 amp status force Forces Acting on CBRG180 amp status compart Compartment Properties amp status category Category Status for Selected Parts amp status draft Draft Mark Readings Table 1 Command to Report Association M_STAB Discussion Stab_ok Let s first review m_stab dat The first command use_mac stab has a similar format to that which we found in istab dat use mac install This command tells MOSES that we will be using the stability macros MOSES comes with a set of tools for the more frequent analyses Among these tools are stability finding allowable KG finding allowable deck load and transportation analysis We will be working with the stability macros The command use_ves enables us to use a vessel from the vessel library Then we define two nodes bcg and ccg In MOSES part of the geometry is defined with nodes and node names begin with the symbol Please see the following link for a more
120. idered to be at the height of the jacket launch leg centerline above the barge origin Also B1 i are the selectors for the nodes the BODY _NAME 1 which will be used for connecting the jacket to the barge body Page 148 We know our barge body name is barge but now we need to go to the figure towards the bottom of the page to get a better idea of what values to put in for XB YB and ZB From this figure we see that XB YB and ZB are locating the trailing edge nodes on the barge Please note that they are locating the centerline of the launch leg The values used in the command file differ only by a sign on the YB value The starboard side leg has a positive and the port side leg has a negative The last part of the command requests a selector B1 i however we have put B T and xB We could have used a selector to pic the top nodes on the barge or we could have made a selector to pick the nearest barge node This is an advanced exercise we see that for this command it is acceptable to shortcut a selector for a search with a wild character The launch leg will search for the nearest barge node to make the connection The launch leg connector has to make this determination for each step during the launch Each time the jacket moves the connection points have to re evaluated Depending on the location of the jacket the connectors are turned on and off For the starboard leg it will look for the nodes ending in T For the port leg
121. ile For the DAT file we are interested in two lines at the top and a section near the bottom If you open the DAT file the first two command lines at the top read use mac install amp dimen save dimen feet kips In order to use the automated installation macros you need to have the use_mac install command near the top of the DAT file And of course you need to tell MOSES what units you will be working in This is done with the amp dimen save dimen feet kips command Now go almost to the end of the file lines 60 through the end Here we tell MOSES to use one of the vessels cbrg180 from the library Next we set two variables port_nod and stbd_nod If you review the file box dat you will see that the four points are at the bottom of the piece labeled box The point names are selected to help position the box on the barge The point names are the two characters after the x symbol The points that begin with the letter p are on the port side and points with the letter s are on the starboard side The points that end with the letter s are at the stern while points that end with the letter b are at the bow The rest of the file box dat will not be discussed here The next three lines tell MOSES to place the box model 42 ft from the bow with the midpoint between the starboard and port points on the centerline and 6 896 feet vertically from the barge deck Normally the word following a
122. ilibrium You can see how both bodies are moved 13 87 meters in the positive x direction and both bodies are tilted Also the command amp connector TAUT L_HORIZONTAL forc sets the tension in the hawser to 51 2 mtons Which is close to the 54 mtons that is expected When the amp equi omega 1 command is used equilibrium is found in 5 iterations This means our repositioning was very close When we report the configuration the force and the force in the connectors we see that we are within tolerance for the equilibrium position The reports are in the output file Remember we are looking at the row labeled Inertia for both bodies Just like the mp_moor analysis three dynamic analyses are performed linear fre quency domain analysis spectral frequency domain analysis and time domain anal ysis Most of the reports reference the hawser connections In two body analysis a great deal of importance is placed on avoiding collisions This is why the output is con centrating on the positions of xTAUTT TAUTB and the tension in the hawser TAUT In the time domain analysis the command rel mot is used The relative motion between TAUTT and TAUTB and TAUTB and TAUTT is reported This might at first glance look like we are doing the same thing twice It is a prudent measure to report the results from each point The reference for this command is at the following link http bentley ultramarine com hdesk ref_man ppo inte htm REL_MO
123. is what section looks like C1 5 10 2 V1 5 10 20 C2 10 10 3 Page 16 V2 10 10 20 C3 15 10 5 V3 15 10 20 We need to first define the points before we use them in the compartment description This file is also heavily commented Each of the point defintions is followed by a short description of how it will be used It is a good idea to try to pick names that will make the output easier to use Here each flood valve has a point with the letter C and each vent valve has a point with the letter V This is just for convinence In the next sections the compartments along with the valves are defined The same format is taken for each compartment so this discussion will focus only on the first amp describe hole vi v_valve area 3 14158 5625 point V1 amp describe hole hci f_valve area 3 14158 5625 point C1 amp describe compartment C1 holes Hci V1 pgen perm 0 95 diftype none plane 0 10 rect 0 6 6 end_pgen The first two lines associate the points with a valve The manual reference for this command is at the following link http bentley ultramarine com hdesk ref_man cmp_int htm amp DESCRIBE HOLE The first step is to define each hole and associate it with its intended use For the vent valve we are naming it V1 and have used the type designation of v_valve The two options area and point tell MOSES what area and location to use These are options and if we did not use them MOSES has defaults i
124. it will include all the barge nodes It will however pick nodes ending in T because those nodes are at the top of the barge and nearest the leg For the options TPIN we need to concentrate on the lower figure This option is locating the tilt pin Please pay close attention that TPRIDEP is to the centerline of the launch leg XP YP and ZP are in the barge BODY_NAME coordinate system The last two options FRICT and BEAM are for the coefficient of friction and the section properties of the tiltbeam We still need to establish the coordinate system for launch Here we need to read the 2nd paragraph under the Tiltbeam Geometry figure The order of the input of the ASSEMBLY LLEG command is important as it is used to establish the launch coordinate system of the jacket The axes of this coordinate system are set as follows The X axis is parallel to a line connecting J 1 and J n and is directed towards J 1 The jacket is launched in the positive X direction The origin of the system is midway between the trailing joints given on the first and last ASSEMBLY LLEG command the Y axis is along the line connecting the J n on the last ASSEMBLY LLEG input with the J n on the first one input The Z axis is determined from the right hand rule Remember the table at the begining of this discussion It is the starboard leg that should be defined before the port leg if the launch direction is towards the stern That concludes the
125. ith each analysis that a standard set of column headings for the statistics report was not developed Please notice how the statistics command uses the numbers listed by the command vlist The Disposition Menu has other ways to present the results The most popular being extreme and plot Please consult the manual for these two commands Exercise A Run the file MOSES should end in interactive mode Type CTRL G This should bring up a tab in interactive mode but the screen will be all blue This is because MOSES tries to put in all of the mooring system Type amp picture starb render gl connector no This creates a picture of only the barge amp picture starb reset This changes the picture to a wire frame The picture shows the barge and the mooring system The following picture is what you should get Page 90 Sample of Multi Point Mooring Event 301 0 Figure 38 Mooring set up for mp_moor analysis Type CTRL F to finish MOSES Now let s test some of the descriptions I have written earlier Change mp_moor cif to read CONNECTOR h anchor 45 20 wire MLA END amp device primary screen amp eofile Now get a rendered picture as you did before You will see that the mooring lines fall straight to the bottom and that the anchor is placed about 20 ft from the fairlead Since we have not yet told MOSES to move the anchors this is exactly what the picture should look like Exercise B Change
126. l three solutions we enter the structural menu with structral and exit the strucu tral menu with end For all three solutions we create a short output in the structural post processing menu We enter this menu with the command STRPOST and exit it with the command end The command we are going to be focusing on is LCASE It can be found at the following link bentley ultramarine com hdesk ref_man str_Icas htm For the structural solution we are going to focus on time steps 0 25 30 35 37 and 40 Two before tip three between tip and separation and one after separation For the approximate solution we have LCASE lleforce 1 2 50 process 0 25 30 35 27 40 S_PART JACKET S_REST SPRING SSOLVE The manual tells us that Before tipping a single distribution will be generated After tipping the distribution will be composed of two trapezoidal distributions each TBLEN feet or meters long which are symmetric about the tiltpin The relative intensities at the pin and at the ends of each distribution are goverend by the two parameters QBEG and QMID The load distribution between tipping and separation is respresented by the rocker arm load in Figure 62 Rocker Arm Lad Distribution QMID QBEG TSLEN gt ROCKER ARM LOAD DISTRIBUTION FIGIIRF 7 Figure 62 Rocker Arm Load Distribution For the better before tip solution we have LCASE process 0 25 30 35 27 40 S BODY JACKET S_REST amp LWAY SSOLVE NONLINEAR
127. l write over any files in the ultra directory If you choose to work in the ultra directory you run the risk of losing your work For each exercise I tried to have a set of topics reference files other commands to use and a purpose before the discussion The discussion covers by example the topics listed The reference files were used to present the topics In most cases the reference files are part of the standard MOSES distribution Text Editor You will need to view and change the text of many files You are welcome to use any editor of your choice Popular text editors are WordPad VI Crimson Editor Medit Ultra edit and Emacs It is assumed that you know how to use the editor you choose and no attempt will be made to try to teach how to use an editor I do make references to line numbers It will be easier to follow if your text editor shows line numbers Page 1 1 1 Installing MOSES Windows The following are the standard set of instructions for installing MOSES If you would like to watch a video of this please go to the following site http bentley ultramarine com pub download htm The section Install MOSES has an entry for Windows machine Please click were indicated On a Standalone Machine e CD ROM Versions Insert the CD It should start the install procedure If not go to the CD ROM drive often D and double click on setup exe e Download Versions Locate and run the downloaded file It sh
128. l z direction is 1190 63 cos 9deg 1176 02 kips This is where the 188 kips net force comes from With the command amp status tip hook we see what change was done to the boom length Originally the boom length was defined as 200 ft We see from the report Page 106 that the length has now been changed to 221 ft This change resulted from the amp connector amp boom I_tension command Now that the slings and boom line are set up we need to make sure the barge is in equilibrium If we had compartments modeled we could change our ballast configu ration However since we don t we can add a weight In the next command amp weight compute we change the mass properties of the barge so that it is in equilibrium in the current state The current state includes the lightship weight and CG location the buoyancy force and the force from the boom After this command the report from status config shows that the body barge is in equilibrium To verify that the sling assembly has not changed we again report the forces in the connectors with amp status f connector We also ask for a report of the position of joint J1001 to make sure the jacket is out of the water At this point we know that the body barge is in equilibrium but the body jacket is not We are going to let MOSES change the location translation and rotation in our next attempt at finding equilibrium Before we do that we need to turn off the airtuggers
129. le The transportation part of the command file needs to use the ballast option We can make a selector for all the compartments that will be filled to 100 It should read ballast full 100 5bp 95 6bp 95 Disscusion Log and Output File The big difference we are going to see for this analysis is in the run time 3D diffraction takes substantially longer time in comparison to strip theory This will be evident as you wait for the analysis and in the log file MOSES reports every time it finishes the calculation for a wave period Here is what the log file looks like when it calculates a 3d diffraction database Setting Pressure Name for JULIEB to D3 2 Time to Generate 494 Panels For JULIEB Time For 3D Diff Time For 3D Diff Time For 3D Diff Time For 3D Diff Time For 3D Diff Time For 3D Diff Time For 3D Diff Time For 3D Diff Time For 3D Diff Time For 3D Diff Time For 3D Diff Time For 3D Diff Time For 3D Diff Time For 3D Diff Time For 3D Diff Time For 3D Diff Time For 3D Diff 494 Panels Freq 494 Panels Freq 494 Panels Freq 494 Panels Freq 494 Panels Freq 494 Panels Freq 494 Panels Freq 494 Panels Freq 494 Panels Freq 494 Panels Freq 494 Panels Freq 494 Panels Freq 494 Panels Freq 494 Panels Freq 494 Panels Freq 494 Panels Freq 494 Panels Freq Setting Drift Name for JULIEB to D3 2 1 CON MD OK W WO 9 10 11 12 13 14 15 16 17 Time t
130. le you can view the column labels at the end of the column addition more than a few lines down From the results of vlist we see we want to compare column 4 to column 8 and column 6 to colum 9 The comparison plot for shear is shown in Figure 23 and the comparison plot for bending moment is shown in Figure 24 The plots are also in the answers directory You will notice that for the shear comparison the structural analysis line is jagged This was expected In the command file there is a message REMEMBER the load is distributed but the buoyancy is lumped at the nodes The moment comparison is smoother but still off by the fact the buoyancy is at the nodes Shear Comparison 7g0 Structural Traditional 590 420 280 T a wq 140 Shear 103 9 as Mit r T r T T T T 1 120 160 200 240 280 320 360 400 Long Location Figure 23 Comparison Shear Page 53 Moment Comparison o Strusia Tr itional i i C COY fi f i N if lt S jj T Fj j j 2 j x W i 7 2 j Pg j o f Yi ji m ji z j oS j X if X j Y y N fA g A H f a fy oy Y z X y he A D lt A 3 1 1 1 1 1 r 1 0 40 80 120 160 200 240 280 320 360 400 Long Location Figure 24 Comparison Bending Moment Exercise A Earlier we said that it is important that
131. led Tank Capacities for XXXX where the XXXX is the compartment name The columns we are interested in here are the Free Surf Moment Trans and Long If we review the Buoyancy and Weight report we see that the 3XXX and the 5XXX compartments are filled to 85 The Tank Capacities report the free surface moment to be 562 for the 3X XX and 561 for the 5XXX We will work with 562 for the calculations here Calculating the free surface is simple enough We should be able to verify the change of 0 2 meters We know that Free Surface Correction is the Free Surface Moment divided by Displacement fs_cor fs mom displacement 2 3 1 So far we have the free surface moment For the displacement we look at the buoyancy and weight report to get the draft of 4 60 meters or we can look at the curves of form for the displacement 11199 47 m tons This would be 10 929 m3 If we do the math we find that each compartment reduces the metacentric height by 0 05 meters Since we have four compartments the metacentric height is reduced by 0 2 meters And we see this is true The difference between the GM with 12 60 m and without 12 80 m free surface correction is 0 2 meters What else does this influence The free surface correction also influences the righting arms Here the righting arms are reported and plotted The reports titled back to correct include the free surface correction As you can see the righting arm without the free surface cor
132. line Therefore the results of the amp weight compute which were based on a boom tension of 1000 kips are no longer valid Now we see that the barge is out of equilibrium by nearly 188 kips Since we are trying to analyze the case where the jacket is in the air we need to check to verify that the jacket is above the water We can verify this by checking the location of one of the jacket corners specifically the location of J1001 To make Page 107 this check we use the string function amp point coordinate j1001 g String functions actually query the database and return the values asked We need to ensure that we are telling MOSES what to do with the return values In this case the command amp type location of j1001 amp point coordinate j1001 g tells MOSES to put the results in the log file which shows location of j1001 155 8654 248 6527 4 199845 We can see from the coordinates of j1001 that the jacket is not completely out of the water In order to analyze the case with the jacket above the water we are going to again change the length of the boom sling This is done with the amp connector amp boom l delta command The boom sling will be shortened by 8 feet This should lift the jacket from the current 4 feet to a 4ft First we check that the boom sling has been changed by 8 ft Earlier the command amp status tip hook reported 221 93 ft for the boom line length We see that now after the change it
133. long because it includes all of the cases created with the Icase rao command The second time through we report only the load cases we are interested in The results of the structural code check are presented in various forms in the last set of commands Usually a project wants to review the static stillwater case separately from the dynamic load cases Here we present the results of the code check with the command beam code load stillw In the next command beam code load load we get the summary of the results for all of the load cases Only the case which resulted in the highest code checks is reported For our analysis there is predominantly H090 but there are some H135 still listed Just to show that the other load cases are available the last command beam code load s135 presents the results of the code check for only the 135 loadcase This concludes the strength check of the transportation The last set of commands computes the fatigue check To do fatigue you need to give MOSES the environments and the duration of each environment For our tow we have all of the information in a separate file named env dat located data env dat0 This file and its format have basically been un changed for a decade You need to change the numbers to set the velocity vel the total time tim and the length len variables After that you define the environ ments with the first value being the length of time the transportation is exposed to
134. lumns One of these variables is filled each cycle These variables are populated with the string of values in column 5 We will be using them when we produce the plot of the three distances together In getting the values for the event we do not need to cycle the name The list of events is the same regardless of what point is being referenced It is inefficient to have the same values recorded three separate times I however was not willing to put in the extra keystrokes to make the variable event be filled only once I left the commands in the sloppy form here Back to investigating if the two bodies collide In setting the collision variables cedgel cedge2 and cedge3 we were monitoring the distance on the barge xy plane between the two bodies If a negative distance is recorded as a minimum then a collision has occurred We need a way to ask MOSES if the value recorded for the collision variables is negative One time is sufficient we do not care if it occurs multiple times What we are going to record or change is the value of bang Once the value of bang is changed to true we do not want it changed back to false and we do not care for it to be reset to true a second time First we check the current value of bang If this value is true then we do not need to change the value and can skip the checking If the value of bang is false then we will check to see if it needs to be updated Checki
135. ly Morison type forces will be calcu lated Figure 42 shows the section of the log file where the hydrodynamic database is calculated The messages are only about the tanker An environment that has waves current and wind is defined with the command amp env This is followed by some amp status reports Page 97 File Edit Tools Syntax Buffers Window Help auDA acl Aala AAA TAa a gt hydrodynamics gt g_pressure tanker HEADING 6 22 5 96 186 Setting Pressure Name for TANKER to TANKER Time for Strip Theory For TANKER Setting Drift Name for TANKER to Time to Sum Pressures For 246 Panels on TANKER Time To Set Up Convolution gt end gt amp ENU USE sea ISSC 186 3 68 9 19 CURRENT 7 186 WIND 26 8 186 time 666 56 gt amp status config CURRENT SYSTEM CONFIGURATION Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified Location and Net Force at Body Origin Location N Force Figure 43 Hydrodynamic Calculation Log Again you will find this approach in many of our samples A review of the mean forces is reported after the hydrodynamic database has been calculated and the environment has been defined r lt a y TA 10g00001 tet C test calm calmans GVIM3 balak File Edit Tools Syntax Buffers Window Help Aaaale Lal BARSAAT aala A gt amp status FORCE f FORCES ACTING ON BUOY Process is DEFAULT Units Are Degrees Meters and M To
136. mands shows further detail of the buoyancy and weight b_w the compartments and the valve hole data v_hole Remember the manual did say we could observe the resulting change in ballast with the amp status compartment command The results of these amp status commands confirm that the compartments are empty and the valve are closed Page 20 TA 10400001 txt C test open_valve static_open ans GVIM o nn Fle cit Toots Syntar Butters Window elp m i GABBS SeE X SB BRA AAAI TAa R gt amp status compartment COMPARTMENT PROPERTIES Results Are Reported In Body System I Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified Fill Specific Ballast Full Name Type Gravity Maximum Current Min Curr c1 CORRECT 1 6258 6 66 6 66 6 666 CORRECT 1 6258 6 66 6 68 6 668 CORRECT 1 62568 6 66 6 68 6 66 6 666 HOLE DAT A Results Are Reported In Body System Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified Hole Location Normal Friction frea Name Type Y 2 Factor F_UALUE 16 66 r 6 66 20 l U_UALUE 16 66 s 1 80 20 F_UALUE 16 66 6 68 20 U_UALUE 16 66 1 80 20 F_UALUE 16 66 6 68 20 U_UALUE 16 66 20 Figure 6 Results of amp status for Event 1 Three figures are generated to get an understanding of the setup After inmodel c3 c2 C1 Figure 7 Comp
137. means that if the barge has a slight roll the xy plane will have that rotation and will not be parallel to the global xy plane We will produce a plot of the distance to each edge point separately Then we will produce a plot of the distances plotted together The results of vlist in the log file show that for each loop cycle the column variable names will only differ by the 1 2 or 3 after edge So we can use the same column number to get the data of interest A review of the log file shows that column 5 is always the position magnitude and column 1 is always events We are using a new command set_variable Up to this point we have been using the multi menu form of the command amp set to define variables Here the command set_variable makes the association with the data that is in the Disposition Menu First we are going to find the minimum distance It does not matter when the minimum distance occurred The command set_variable edge min 5 5 finds the minimum of column 5 each time the loop cycles For this discussion we are going to refer to these as the collision variables The first time through the loop cycle the collision variable is cedgel the second time cedge2 and the third cedge3 Individually these variables will be set to whatever the minimum value happens to be for that time through the cycle The second set of variables are redgel redge2 and redge3 We will call these the distance co
138. mn headings with vlist We use this information to get a plot of the barge motions then we get a plot of the jacket motions Review of the plots shows us something that we could not see in the linear analysis The system as defined does not have a mooring system Therefore the system wanders in the negative y direction it is being pushed by the 90 degree waves The range of motion of the barge is 60 ft and the range of motion of the jacket is 150 ft We need to look at the phasing of the two motions to see if there is a strong possibility of collision To monitor this we will use a variable named bang To begin the investigation we are going to make the assumption that a collision does not occur So we set the value of bang to false In the next set of commands we get relative motion information This type of data was not available in the frequency response section The command rel motion ptn1 pnt2 tells MOSES to find the motion from the first point to the second point We will be using the three edge points that were designated as points of interest in the data file amp describe interest associate edge Page 114 Here it gets interesting because we are using a amp loop command to cycle through the list The first time it will use edge edgel the second time it will use edge edge 2 and the third time edge edge3 On all three cycles the distance to jacket node j1003 will be measured in the xy plane of the barge This
139. mp token several times in the Build Graph Menu so it would be worth reviewing the format in the manual By this time you have probably figured out that the command amp buildg will put us in the Build Graph Menu The command with option amp buildg brief here is much like the command with option plot no We are telling MOSES to just accept our input and not ask for verification Since we are using the brief option we are going to have to pay close attention to format The next four lines with commands no comment character are the labels for the column headings Page 116 The next line is blank It is important that the line immediately after the last column heading is blank the comment character is after the blank line This is how we tell MOSES that the list of column headings has ended As the comment in the command file reads the next set of commands populates the table We are using a loop again We start with the first event and the value for each edge associated with that event The table is being populated one row at a time A row is populated each time through the loop When the data input has been completed jjj n the loop is exited and we have another blank line The blank line is important here also This is how we tell MOSES that the data input has finished When you review the log file for this section you will see that this section of the log file is blank MOSES usually does not echo to the log file inside the amp l
140. n discussing the command file before reviewing the log and output files For this exercise it will be much easier if we discuss the log file and its contents as we are discussing the commands as they occur in the command file Please run the analysis and create the log file so that the rest of this discussion can make sense Do not delete the database or the answers directory but instead restart After this restart in the sink ans directory there will now be a log00001 txt out00001 txt and a log00002 txt Once the MOSES window appears type CTRL G This should bring up a rendered figure of the final event With the mouse you can move the green bar near the bottom to left near 0 0 Then you can press the Play button and watch the simulation Now we can discuss the commands For this exercise we are not going to merely discuss the commands but we are going to review them in the log file as well We are familiar with the commands at the top of the CIF file from previous exercises The first new command we encounter is amp parameter The command amp parameter sets many of the basic parameters in MOSES Please see the manual page for all of the Page 59 available options This is the first time we are going to work explicitly with a Process In MOSES a process has events We will be doing a time domain process We need to tell MOSES how long to make the process and how many events or how big the steps are going to be This i
141. ng is done with the IF statement amp if not bang amp then and ends with the command amp endif Within the IF statement we set the value of bang to the results Page 115 of the amp logical statement The logical statement simply returns either true or false In this particular instance we are asking MOSES to see if the value of the collision variable is negative less than 0 If the value of the collision variable is negative then bang is set to true and the variable will not be changed again in the loop cycles Before the loop cycle completes a plot of the relative position still working with columns 1 and 5 the distance between the two points is made for each time through the loop The command amp endloop tells MOSES where the cycle returns to the top and for the last entry edge3 the loop cycle is exited We have put a great deal of effort into the collision values We leave ourselves a note right after the loop to let us know the result I am referring to the three command lines that begin with amp type Review of the log file shows that the values for the variables are substituted We see from the short message that the barge and jacket did not collide We also see from our short message that there was a minimum of 8 4 ft clearance between the two bodies This is actually a big deviation for the 1 ft clearance we determined with the linear analysis If this were a real project we would have probably only used t
142. ns Unless Specified Results Are Reported In Body System Type of Force x y 2 MX MY Hz Weight y R 8 a Buoyancy 8 ai Wind is is a 8 Viscous Drag s m 6 Inertia I o Added Inertia 6 Flex Connectors 8 Total s 8 FORCES Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified Results Are Reported In Body System Type of Force x Y 2 MX MY MZ Weight 6 66 6 66 3 4065E5 6 55573726 6 Buoyancy 6 66 0 00 346659 44 6 55573719 6 Wind 12 24 6 60 1 61 6 533 8 Viscous Drag 13 11 6 66 6 66 8 288 6 Wave Drift 29 26 6 64 85 23 8 13638 7 Inertia 54 55 0 04 83 62 1 14457 6 Total 6 66 6 66 6 66 8 8 6 w amp e ee Figure 44 Force Report Page 98 The next step is to find the mean offset position We could just start using the amp equi command until we achieve a position within tolerance Or we could reposition the two bodies to position that is near equilibrium We see that the tanker has a total environmental force of 54 55 m tons in the positive x direction This force will be transmitted to the buoy via the hawser Now if we look on the Restoring Force table we see that a force of 54 4 m tons is also the excursion of the buoy 14 039 meters We know the excursion is not going to be exactly 14 039 meters There is also a mean force from the buoy that needs to be accounted for Also the buoy will probably tilt The section labeled Set Initial repositions the two bodies so that they are near equ
143. ns is not welded There is a possibility that there could be a temporary disconnect at these locations This disconnect would make the problem non linear The second time through the structural solver we define the RAO load cases This just creates the real and the imaginary cases for a regular wave and the headings This does not combine the RAO and the wave spectra This time through the struc tural solver s_part has jacket can and tiedown This is because the dynamic loadcases are supposed to represent a situation where the tiedowns have been added At the conclusion of the computation we just know that we have done the compu tations We will have to go into another menu to get a report of the results That is what is done with the Structural Post Processing strpost menu The first thing done in the post processing menu is to combine the RAO load cases with the wave spectra cases spect When we review the tables in the output file the load cases Page 131 will have the names listed after the spect option This concludes the computations for the structural strength analysis The rest of the commands control the contents of the output file First we make a selector to include all of the spectral loadcases Then we report the multipliers for the currently defined structural load cases This is done with amp status r_case The first time through we report all of the available load cases This first list is rather
144. o the jacket top at point j0501 The values used in the tug option indicate direction Page 104 and length Essentially the combination of tugs are going to act in the 45 degree direction The next set of commands define the tip hook assembly The tip hook assembly consists of a boom line and four slings First we attach one end of the boom line to the boom tip and one end of each sling to the appropriate point on the jacket This is what is done with the five connector commands defining boom sling1 sling2 sling3 and sling4 Now attach all 5 segments to a common hook This is much like attaching the hook hanging from the boom to the four slings attached to the jacket The attachment of the 5 segments is done with the assembly t h_definition command At the end of the assembly t h_definition command there is the option initial From the manual we learn that using this option instructs MOSES to move the body so that the hook point is directly below the boom point So far we have not checked the geometry to verify the designated sling lengths will work with the position of the bodies For now the initial option only places the hook below the boom We are not expecting the slings to be tensioned or slack Now that our connectors are defined we can exit the model edit menu and complete the analysis setup To exit the model edit menu we issue the end command Sidelift Command File Discussion Connecting the Two Bodies Now th
145. o Sum Pressures For 494 Panels on JULIEB Time To Set Up Convolution CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP 0 50 2 71 2 70 2 68 2 70 2 71 2 85 3 05 2 75 2 74 2 73 2 74 2 78 2 80 2 87 3 09 3 21 4 08 0 19 0 03 When we review the pictures and the tiedown ends we see that some of the tiedowns did not land on the barge Mathematically all the rigid connections are made and the analysis is completed We do need to make these visual checks on the pictures Page 144 or the checks of the ends reporting to make sure our situation is real Other than that the presentation of the log and output file is very similar to those we have seen before Exercise A If you look closely at the tiedowns located at the stern starboard side you will see that they do not land on the barge This needs to be corrected We can use the i_connector xy_delta form of the automated installation command to fix this quick Change the bottom of data file where the tiedowns are defined to read iconnector v_can vcan port_nod stbd_nod iconnector 4_tie tiedown port_nod j0201 j0301 j0401 i cconnector xy_delta tiedown 1 5 1 5 j0101 icconnector xy_delta tiedown 1 5 1 5 j0101 icconnector xy_delta tiedown 1 5 1 j0101 i cconnector xy_delta tiedown 1 5 1 j0101 Page 145 6 3 Launch Introduction This exercise presents
146. og file Note the results with p_m2 have a larger values The plots do at first glance appear to be the same but when you focus on the values you see that the loading conditions have to be different We are going to try several variations of the ttweight command to see if we can figure out what the amp weight command is doing Exercise B 1 Copy the p_m dat file to testc dat 2 Copy the p_m cif file to testc cif 3 Before the amp describe part command add the weight commands to read as follows in the dat file bcg 200 0 30 weight bcg 20589 32 129 129 ldist 0 400 This again changed the shear and bending moments Here we know that the 20589 weight is being modeled as evenly distributed from bow to stern Do the shear and bending moment curves also show this Exercise C 1 Copy the p_m dat file to testd dat 2 Copy the p_m cif file to testd cif 3 Change the distribution of the cargo weight See changes below Page 41 cen 0 0 0 weight cen 5000 ldist 200 200 What this does is distribute the weight of the barge and the cargo evenly between x location 200 and 200 Exercise D 1 Copy the testb dat file to teste dat 2 Copy the testb cif file to teste cif 3 Change the weight commands to read as follows bcg 200 0 30 weight bcg 20589 32 129 129 ldist 180 220 2 Change the cargo weight commands to read as follows cen 0 0 0 weight cen 5000 ldist 20 20 What is the buoyancy force per length
147. oints ppp anotate points After reorienting the jacket the next set of commands locates the bodies relative to each other When locating the jacket keep in mind that we are now using the new jacket origin and coordinate system The amp instate command is written on two lines however with the line continuation character it is all one command The barge is set at a 20 foot draft but its bow centerline is kept at the global X Y origin The jacket origin is set 143 ft in the positive global x axis 143 ft aft of the barge bow 200 ft on the positive global y axis 200 ft starboard of the barge centerline and finally the origin the midpoint of the vector between nodes j1003 and j1001 will be 1 foot above the water level with a 9 degree pitch the top elevation will be pointing up Now that the bodies are positioned we can define the connectors The connectors are added in the model editing menu which is entered with the command medit First we define the classes We will need classes for the boom line the slings and the hold back lines tuggers We define the classes boom and sling as having an outer diameter of 3 inches and a length of 200 ft and the class airt to simulate the hold back lines In this case we will simulate the hold back lines with a small tug boat but we will refer to it as an air tugger for this analysis In the next set of commands two air tugger connectors are defined as connecting t
148. onvention where tension is positive Therefore any positive axial loads indicate uplift in the support As you can see the installation macros made special load cases to keep track of the load signs In this manner we can ensure that any wave loads would increase the axial shear and bending moment of a member not decrease it We did not take this precaution in the native commands files When you compare the results of the structural code checks you will see that the results are different You will also notice that the installation macros have taken the extra effort to take the tiedowns out of the section where the still water case is reported In our native command file the tiedowns are reported as part of the still water case as having 0 loads When you look at the graphical representation of the structural results you will also see different colors In the installation tools results the vertical members fail this is in comparison to the native command where the vertical members pass We tried to make the installation tools easy to use The purpose of this exercise is to show a comparison A secondary purpose is to show the workings of the installation tools and show that the installation tools provide a rigorous method You are welcome to use whichever method you prefer for your projects Exercise A e Start with the deck from test files sac2 see ultra hdesk runs tests convert directory e Convert this file and transport the resul
149. oop After the loop we see the results of vlist are as we input in the lines above Finally we use the plot command to make the plot with all four sets of data on one plot Then we exit the Build Graph Menu with end The next command is just a message to ourselves to make sure we are in the Main Menu We will be doing a structural analysis to satisfy the final project requirement The only way to enter the structural solver is through the Main Menu so we want to make sure that is where we are Inside the structural solver we will need to specify which restraints to include in the structural solution Since we are only looking at the jacket structure only the four slings attached to the jacket are required This is why we need to set the selector restraint to only select the slings attached to the jacket We enter the Structural Solver menu with the command structural We tell MOSES which load cases to use with the command Icase process Remember we have set the value of f_time to the second occurrence of a slam event and the project requirement is to have a load case at time event 5 In the next command s_rest we tell MOSES which restraints to use for the structural solution This is followed by the command s_part which tells MOSES on which part to perform the structural solution If this had been a single body analysis we would not have had to be so specific with all of these commands Finally the commands reduce and expand perform the
150. or each item Since the part coordinate system for the two parts is different then reporting them on the same table and then for the last row summing the results would be misleading This is why we want to use the Page 125 amp rep_sel command for these reports a E 1 out00001 txt CAtest tow_native native ans GVIM File Edit Tools Syntax Buffers Window Help auala ald AATE A HOSES 9 December 2611 CATEGORY SUMMARY FOR PART JACKET Process is DEFAULT Units Are Degrees Feet and Kips Unless Specified Results Are Reported In The Part System of Part JACKET Weight Buoyancy Center of Gravity Center of Buoyancy Category Factor Factor Name Weight X Y 2 Buoyancy x v 2 EXTRAS 1 666 1 606 JACKET 3666 66 25 06 6 66 25 60 6 66 6 66 6 66 6 66 STR_MODE 1 666 1 606 BEAM 107 67 25 08 6 66 25 60 214 42 25 08 6 66 25 60 ota 3167 67 25 60 6 66 25 66 214 42 25 06 6 66 25 60 z 73 1 3 Figure 47 Category Summary Table The next report is on classes Classes do not belong to a part so the reports ti tled Class Dimensions and Material Redesign Properties show classes and material properties for the jacket the tiedowns and the cans For the tiedowns we have reports titled Beam Properties and Beam Ends Both of these reports are useful in verifying that the tiedowns are modeled as the project desires The beam properties summary is where we can verify t
151. ositions show that there is a slight difference between the body coordinate system and the global coordinate system This is showing the difference resulting from the equilibrium roll and pitch The next command needs to be looked at a bit closely Here we are asking for a report of the status of the pressure on the defined holes amp status p_hole Please note that this is the static situation at the current event All of the holes are going to show that their current state is open Their current state is in a static scenario We have not told MOSES that we will be flooding dynamically nor that this is to be associated with an event The command amp status v_hole produces a status of the valve data The valve data reported is the hole type the location the normal the friction factor and the area Page 65 Please notice that the coordinate system being used here is our new coordinate system that was defined with the amp describe part command From this point forward it should be similar to that which we discussed on sink cif In the next command we perturb the system a slight bit and report the position of the bottom of two of the legs We define an environment so that we can have a time to work with Then we open the valve and see what happens Even in the output we report many of the same quantities After you run it you will see in the log file that the simulation ended due to capsizing If you look at the movie you will see
152. oth the frequency and time domains Many of the steps shown are not necessary to perform the analysis We use them to show the many options the user has to check the status of the system and evaluate the configuration The discussion assumes that the reader has the command data log and output file available For this exercise we will e Check the motions of the barge and jacket e Check the jacket for slamming events e Check the tensions in the boom line and slings We will assume that the crane capacity is 1000 kips e Perform a structural analysis of the jacket at event 5 and the 2nd slam occur rence Sidelift Data File Discussion Many of the commands in this file will be familiar to the person that has worked all of the exercises to this point For the most part this file is going to be discussed in general terms with some discussion on the new commands If there is a command that is unfamiliar please review the earlier exercises or refer to the reference manual Page 101 Data that we will need for the discussion of the command file are the general dimen sions of both bodies The barge general dimensions are length 500 ft breadth 170 ft and depth 50 ft The general dimensions of the jacket are bottom elevation width 96 ft top elevation width 45 ft and height from bottom elevation to top elevation 201 ft The top section of this data file has an extra body that is not used for the analysis but is used for
153. ould be called something similar to moses_download_win32 exe e Both Versions Press Next until you get to the Choose Components screen If you want to keep your old MOSES install select Backup old files This will create a directory ultra_p with your old MOSES install and settings Associating Files registers MOSES s CIF and DAT extensions with Win dows so you can double click on them This is recommended for most machines but is not necessary for installs on a file server Do not install the Sentinel Hardkey Driver unless you are using a Sentinel Hardkey and this is the only program that is using it Otherwise this can conflict with previously installed drivers Allow the installer to complete You should now be able to double click on any cif file on the machine and have MOSES run Page 2 On a Networked Machine instructions for IT staff and advanced users On the File Server Install the software by following the steps above Change the permissions as follows ultra read all files and subdirectories ultra data progm read write ultra data site read write Share the ultra directory or a parent directory of ultra On the users machines Mount the ultra directory as a drive we will use U in this example There should be a moses exe under U Double click run moses exe This will bring up a MOSES window MOSES will ask for a file name
154. ound in jacket sac This uses one of our macros and it makes all of the changes and creates the check files for you Run this CIF file and answer the following questions Exercise A 1 How much does LOADLC3 weigh 2 Where is the center of gravity of the elements 3 What is the total buoyancy Exercise B Start with the sss inp file in the samples data directory Convert the model and call it jack dat You will need to add the command categ brief to the section within the amp summary 1 Where is the center of gravity of the elements 2 What is the total buoyancy Page 57 4 Motion 4 1 Dynamic Flooding Topics e Dynamic flooding of a compartment e Setting the initial pressure in a compartment Reference files e ultra hdesk runs tests compart sink cif and sink dat e ultra hdesk runs samples how_to up_damage cif and up damage dat The two sets of files are intended to complement one another In the sink analysis a barge compartment is dynamically flooded In the up damage analysis a tubular jacket leg compartment is dynamically flooded In both cases the intent is to show how to model water entering a compartment in the time domain The potential uses for this set of commands are the dynamic flooding during an upend and the accidental damage to a compartment Sink Dat File Discussion Let us begin with discussing the DAT file We have two new parts of the barge defined here the draft marks and the valves The draft m
155. pe for compartments 1PSS 3PSC 3SBC 5PSS and 5SBS Specifying the fill type was done with the command amp compart app_none tow If we read the manual we find that APP_NONE uses the correct CG when it is filled and uses zero for the derivatives no free surface correction Now if we return to the output we see that GM is not reported in first Page 11 GM is reported as 12 60 meters in second GM is reported as 12 80 meters in third The three pages from the output are shown below al But00001 tet C test samples hystat results fs_mom ans GVIM Se File Edit Tools Syntax Buffers Window Help ABRS 9SE XSUS BRASSA THA7A MOSES Daaa February 9 2011 Ol first BUOYANCY AND id Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified Results fre Reported In Body System Draft 4 66 Roll Angle 6 66 Pitch Angle 6 66 Wet Radii Of Gyration About CG Mt K X 6 36 K Y 17 86 K 2 18 36 Center of Gravity Sounding Full Name Weight BEGRass H Yor no oaS Saeeses a Part SMITS LOAD_GRO 7706 60 46 08 I 6 66 4 32 Contents SPSS 872 85 81 15 10 29 3 05 6 16 166 66 SSBS 872 85 81 15 16 29 3 65 6 16 166 66 Total 9452 36 52 56 6 66 4 69 Buoyancy 11199 47 48 16 6 66 2 34 2 52 66 3 K A Figure 4 Results of amp status b w when not in equilibrium Page 12
156. pears there should now be a b_run ans and a b_run dba directory The DBA directory is where the database is located All of the files in this directory are for computers i e not for human eyes The files in the ANS directory contain the answers ANS is short for answers At the conclusion of the MOSES analysis we will normally look at the log and the out file which can both be found in the ANS directory The log file is a log of the commands used to perform the analysis The out file is the results of the calculations In most exercises you will be asked to delete the ANS and DBA directory to recreate the answers in the results file or to view the results after data has been changed At other times you will be asked to restart the run this means you should access the existing database You restart the run by double clicking on the CIF file You Page 4 should not delete the ANS directory unless you are asked to do so Discussion The Analysis In this analysis a vessel is set at a draft and trim the weight necessary to be at equilibrium is computed then three sets of hydrostatic calculations are reported Three things are done in this analysis The curves of form are computed with the section beginning with the command cform Stability righting arm and heeling arm curves are computed with the section beginning with the command rarm Longitudinal strength is computed with the section beginning with the com mand equ
157. perties Summary Table Pages 10 and 11 of the output are a summary of the SN curves that will be used for fatigue These are included as part of the first section summarizing the input For our analysis we are not changing or adding to this list but we still need to provide the curves that are used as part of the output Finally we make four pictures showing the configuration as part of the input summary The four pictures are created with the amp picture command Page 127 Sample Of Simple Jacket Installation Transportation Analysis on barge E Le E FIGURE 1 Figure 49 Iso view of Transportation Sample Of Simple Jacket Installation Transportation Analysis on barge FIGURE 2 Figure 50 Side view of Transportation Page 128 Sample Of Simple Jacket Installation Transportation Analysis on barge FIGURE 3 Figure 51 Bow view of Transportation Sample Of Simple Jacket Installation Transportation Analysis on barge FIGURE 4 Figure 52 Top view of Transportation Next we perform a stability analysis These are the same commands that were used in previous exercises and will not be discussed here In the next section of commands we produce a set of tables that summarize the system Please note that all of the values are reported in the barge coordinate Page 129 system The last Category Summary reports in the barge part system For this report the structur
158. produced by the commands PRCPOST LAUP STD END If we focus on the Event column we see the time step increases in increments of 0 5 for the first 30 seconds or until tip The time step increases by 0 25 seconds until 37 25 or until separation Then it goes back to increaseing by 0 5 seconds until the simulation ends This is what was specifiec by the option TSTEP The first value indicates the time step before tipping the 2nd value indicates the time step between tipping and separation and the 3rd value indicates the time step after separation Each one of these time steps can be created into a load case and used in a structural analysis Sample Launch a a a Bot Clear BARGE ah o Bot Clear JACKET a W g 3 o Laa v 2 r Rime ge n a a N a Sc K pa g M 8 amp Gal Be wg v S S 5 55 x n no 5 m di e ae 4 H pi S j f Fa M j j j g r r r r T T T 1 0 73 146 21 9 29 2 365 43 8 51 1 58 4 65 7 73 Time Sec Figure 60 Barge and Jacket Clearance Page 151 Usually the time step between tipping and separation is lower than the others This is becuase during tipping a higher percentage of the jacket weight is being supported by the rocker arm By having more time events during this short time more load cases can be defined The command LAUP_STD produces a standard set of
159. quilibrium quickly This is similar to the previous exercises where we first set the body at a condition draft roll trim then found equilibrium The amp instate command orients the body and the amp equi finds the position where the sum of the forces and the moments are very near zero Please keep in mind that for all analyses the program will find equilibrium in a small number of iterations the closer it is to its equilibrium position That is to say we could have also issued multiple amp equi commands until the program found an equilibrium position This plan of action would eventually get us to the same position however we would probably be frustrated by then The results of the amp equi command show that the jacket is in equilibrium with a slight roll and slight trim That is to say the body coordinate system is oriented at a 0 03 degree roll and a 0 89 degree pitch with respect to the global coordinate system In the next section we report the position of the four points we used to define the coordinate system We are using the string function amp points String functions were introduced in the Working with Compartments exercise and will not be further discussed here The only point in reporting the positions of the points is to assure ourselves that an equilibrium position close to the one that we anticipated was found In this section we are reporting the position in the body followed by the position in the global The reported p
160. r about what the element x direction is For the definition we need to look a the CONNECTOR command http bentley ultramarine com hdesk ref_man conn_rest htm 4EULER By default the element system is aligned with the body system of the body to which the first node belongs The use of the EULER option changes the element system For our setup the first nodes are the nodes associated with the body tanker For the body tanker the x is defined bow to stern the y is defined port to starboard and the z is up from the keel The origin is the intersection of bow centerline and keel In the definition of our fender GSPR connectors we are using the option euler 0 0 90 which means that the element x direction will be parallel and in the same direction as the body system y direction The notes within the command file also explain the system change This concludes the connector definition Therefore we exit out of the Model Edit menu with the END_MEDIT command The remainder of the file tests our setup The first report is a geometry report amp status g_connector to check the connection locations This report tabulates the connection points for each body in each body coordinate system This report presents the location of the xfentX and fenbX in the local body coordinate system In the rest of the commands we move the barge along the global y axis and report the forces The force should increase when the distance between the barge and t
161. r preferences Please feel free to change any settings I designate as my preference Page 121 6 1 Transportation Analysis Topics e Transportation analysis with native MOSES commands e Transportation analysis using MOSES tools Reference files tow_native cif tow_native dat tow_brg dat tow_jkt dat data env dat tow_auto cif tow_auto dat Discussion This exercise presents a transportation analysis in two methods The analysis is done with native commands then the same analysis is done with the installation tools The analysis done with the installation tools is considered more complete The objective in presenting both methods is to show some of the steps that the tools are using and to show that if you wanted to go the long way you could An effort is made to make the order of the output file reports in the native command results mimic the order of the output file reports in the installation tools output file The output is presented in three general sections The first section presents a sum mary of the models The second section presents the motions results The third section presents the structural analysis results For both analyses we will be looking at the forces and structural solution of a square looking jacket being transported on a rectangular barge This is a rigid barge analysis The jacket should be placed 200 ft aft of the barge bow and 5 feet above the barge deck There will be supports between the barge
162. r reports the forces in the connectors For our case it reports the forces in the fenders The first move decreases the distance between the two bodies The barge is moved towards the tanker by 1 meter The forces on the connectors report show a force of 100 mtons For the second move it again decreases the distance between the bodies In the last three moves it pulls the barge away from the tanker The last two positions report 0 mtons force in the connectors The second to last position is again for x 0 the last position the connectors would be in tension The command file is exited with the amp fini command Exercise A Change the orientation of the barge such that the centerline of the barge is perpen dicular to the tanker centerline Place the intersection of the barge centerline and bow at the tankers amidships keeping the 2 05m spacing for the fenders Keep the draft for both vessels the same as in the original files The four fender connectors are going to have to fit within the breadth of the barge at the bow Space the fenders with two on the port side two on the starboard side Place them 5 and 10 meters from the barge centerline You should be able to get the same compression forces as we had with the original files Remember that compression in the tanker coordinate system is going to be a positive x force so the use of euler 0 0 90 stays Page 83 5 3 Basic Mooring Topics e Introduction to connectors flexible
163. r the command elat can be found at the following link http bentley ultramarine com hdesk ref_man ele_beams htm ELAT Figure 22 Structural model This concludes the model for this exercise We have defined a model to be used with the traditional naval architecture approach and the structural analysis approach Command File Discussion Now we will discuss the command file The first two commands amp device g_default file and amp dimen dimen meter kNts you will see very frequently With amp device g_default file we tell MOSES to send any plots or views of the system to a file in the ans directory With the amp dimen dimen meter kNts we set the dimensions that are going to be used for the analysis In the next commands the barge is put at a 12 m draft 0 trim and 0 heel This part is similar to what was done in the p_m files The next section is model editing This begins with medit and ends with end We are going to add restraints for the structural analysis In the data file we have added the weight The weight is a force in the negative z direction When the vessel is placed in the water there will be buoyancy forces in the positive z direction For the structural solution to solve we need to restrain the ends Just like in the data file we first define the class Here we are defining a linear spring Page 47 with sprl and spr2 We are defining the stiffness in the x y and z directions for sprl We are definin
164. rboard and p for port Please keep in mind that the draft mark line must be defined from bottom to top MOSES will measure from the first node toward the second node If you reverse the order then you will be getting free board not draft The second new item we have added to the vessel description is the flood and vent valves Flood and vent valves are holes on the outer shell that allow water to en ter or exit an assigned compartment This section starts with the comment compartment In real life they could be vents Here we define a node for the vent valve and label it vent and we define a node for the flood valve and label it flood The defining of the nodes is as done in earlier exercises with the symbol By using the command amp describe hole we are telling MOSES that these are holes on the outer shell For describing a hole we tell MOSES its type size location and a friction factor If we were simply doing a static analysis we do not need to tell MOSES the diameter nor the friction factor In this exercise we will be doing a dynamic flood we want the flow rate to be correct So we do need to make sure the areas and the friction factors are correct Finally the last step in defining the valves is to tell MOSES which compartment is assigned to these holes This is done with the holes option on the amp describe compartment command Sink Commands Discussion For the exercises up to this point we have bee
165. rection has a maximum of 2 41 around 24 degrees Whereas the righting arm with the free surface correction has a maximum of 2 33 around 24 degrees Page 14 Exercise A Change line number 9 to read amp dimen dimen feet kips Take out the amp dimen rem line in the data file Rerun the analysis and see what changed Exercise B In the previous exercise you turned on the wind model with the option cs_cur and cs_win That was for a barge that we modeled just for the exercise Here we are using a barge from the barge library Go to http bentley ultramarine com hdesk tools vessels vessels htm And read how making the following alteration to the DAT file amp set v_cur 1 amp set v_win 1 will turn on the wind and current part of the model 1 What is the wind heeling area at 38 degrees Page 15 2 4 Compartment Ballasting using Valves Topics This exercise is a continuation of how to work with compartments Here the draft of a barge is changed three times The barge has three compartments and each compartment has a valve on the outside shell at a different height Once the valves enter the water water is allowed to enter the compartment When the barge draft is decreased the water inside the compartment up to the height of the valve is trapped inside This will be the first exercise where we use sensors and macros Reference files ultra hdesk runs samples hystat static_open cif static_open dat Discussion
166. ry plot of two bodies Notice on the Rocker Arm Reactions plot that the port side leg leave the barge at a different time than the starboard side leg When we review the output Page 53 Skidway Reactions report we see that the difference is 1 second 108 5 starboard side 109 5 port side We would have to present this to the project to determine if Page 160 this second delay is acceptable Sample Of Simple Jacket Installation Launch From Mid Drit 5 49 M Trim 2 95 Deg 10MS 19 12 5 1 iling Edge Reaction KN 7 i x on Stbd Rocker React Stbd Trailing Edge Port Rocker React Port Trailing Edge Stbd Len Leg on Deck Port Len Leg on Deck aaa T 70 56 2 42 Dis Prom Pin to End of Leg Meters 14 a F or T T T T T T 0 16 32 48 64 80 112 128 144 FIGURE 10 Time Sec 160 140 126 o Figure 70 Rocker Arm Reactions and Distance from Pin Page 161 7 7 1 Answers Getting Started Exercise 1 KML for 12 ft draft 1117 07 ft and KMT for 12 ft draft 75 44 ft 2 Righting arm 17 84 ft for 28 deg roll 3 At longitudinal location 0 400 and 200 ft 4 At longitudinal location 0 400 and 200 ft E Need to review table headers to understand what is being reported Basic Stability Exercise 1 379 30 ft 2 78 13 ft 3 Command RARM 2 5 10 was used 4 The dat file is not echoed in the out00001 txt file 1 938 1 kips 2 5P and 5S
167. s Meters and M Tons Unless Specified Fill Specific Ballast Full Type Gravity Maximum Current U_OPEN 1 6256 356 6 363 7 166 66 6 66 U_OPEN 1 6256 175 3 151 8 166 66 6 66 U_OPEN 1 6256 175 3 151 8 166 66 6 66 gt amp status v_hole HOLE DATA Results Are Reported In Body System Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified Hole Location Normal Friction frea Name Type Y 2 Y 2 Factor F_UALUE 5 66 16 66 2 66 6 66 1 66 6 66 U_UALUE 5 66 16 66 26 66 6 66 6 66 1 898 F_UVALUE 10 66 3 66 6 66 1 00 6 66 U_UALUE 160 66 20 00 6 66 6 66 1 66 F_UALUE 10 66 5 66 6 66 1 66 6 66 U_UALUE 160 66 26 66 6 66 6 66 1 80 Figure 14 Compartments Reports for Event 3 This brings us to event 4 The same set of commands are used but with different values This time we are decreasing the draft This means that when the valve exits Page 26 the water any ballast still in the compartment is trapped For event 4 the water level for compartments with the valve above the water level should have ballast up to the valve KK OK OK OK OK OK OK OK OK OK OK OK OK KK alarm cl TRUE C1 5 10 1 KK OK OK OK OK OK OK OK OK OK OK OK OK xk alarm c2 FALSE C2 10 10 0 KOK OK OK OK OK OK OK OK OK OK OK OK OK xk alarm c3 FALSE C3 15 10 2 Here are the reports in the log file For compartment C3 the water level is at the valve level For compartments C2 and C1 the water level outsid
168. s essentially the piece description In this case the piece is generated with pgen piece generator The commands pgen plane and end_pgen describe the geometry Here we do not define points We are describing the geometry much like a ship plan and let MOSES generate the needed points The numbers 65 to 115 tell MOSES the station locations Remember these stations or PLANE are measured from the bow The first plane will be at an X location of 65 feet from the bow The option rect describes the station properties There is only one station property so that all of the stations will be the same All of the stations will have a rectangular shape with the bottom of the rectangle at Z 15 ft the top of the rectangle at Z 30 ft and the total beam 66 ft If you look up the format for the option rect you will see it asks for a ZTOP ZBOT and a BEAM In conclusion we have a cargo shaped like a box with the mass properties of 1000 kips radii of gyration Kxx 16 ft Kyy 16 ft and Kzz 20 ft Now let s start talking about the CIF file The first part of the CIF file we are already familiar with We know how to put the barge at the desired draft and trim we know how to put ballast in a compartment and we know how to review our setup with the amp status command and options We have familiarized ourselves with the part designated as stability trans in the first three exercises We are going to discuss the general trend of the CIF file her
169. s have options but we are just using the defaults Please consult the manual to find out more about the options It is assumed that the user can find this manual page on the moment without there being a link provided here Let s review the new part of the output specifically the Longitudinal Strength Re sults Is the shape of the curve what we expect Let s also examine two simple force distributions to see what is being presented First let s evenly distribute the weight of the barge and the cargo weight along the entire length of the barge Since our barge is a long rectangular shape the buoyancy force is evenly distributed along the length of the barge 1 Review the output of p m Make sure you have the shear and bending moments reported You might even want to have a plot of this 2 Copy p_m cif to testa cif 3 Add at the top of the file amp device auxin p_m dat 4 Add amp status b_w after the equi_h command to get bouyancy and weights acting on the body Page 40 5 Run the file and review the log file You should see that the amp weight command added 20589 23 kips at x 200 ft y 0 ft and z 30 ft Copy testa cif to testb cif Substitute the following for the amp weight command medit amp describe body barge amp describe part barge xbcg 200 0 30 weight bcg 20589 32 129 129 end_medit 1 Comment out the amp weight command in the CIF file 2 Run this analysis Compare the results in the l
170. s labeled as plots and set weight are familiar to us The new command is amp connector taut INACTIVE This analysis is meant to simulate an offloading scenario In real life the buoy will sit by itself for a time In real life the tanker will approach the buoy on its own This means that each body has to be in equilibrium independent of the other The command takes out the hawser that we have just defined between the two bodies The other commands you will be familiar with is altering the mass matrix so that for each body the six degrees of freedom are in equilbrium The reporting of the categories will show how the mass definition was changed At this point it is a good idea to run the analysis and have the log and output files ready for reference We have seen the Connector Design CONN_DESIGN menu before In this analysis we added some plots But essentially it is the same as that in the mp_moor files We will be using the Restoring Force table created with the MOVE BUOY 180 command We will be referring to it by the name restoring force table Here is a screen shot of the restoring force table Page 96 r E D TA out00001 txt CAtest calm calm ans GVIM2 n e o o moi a a a eiaa File Edit Tools Syntax Buffers Window Help anslog RRA SSA THA7R xxx MOSES xxx T eee 148 February 2013 M TANKER 368666 DWT MOORED TO A BUOY rer rtrrrrrtrrtrrtrrrrrtrrtrtrrrrrrrrrrrtrrrrrrrrrrrtrrtrrtrr
171. s what is done with the new amp env command We need to define an environment because the flooding will be a time domain process Usually when you define an environment the description will include wind waves and current We are only describing the total time and the time step and we are naming the environment null Please see the manual for all of the possible options The next command amp compartment we have seen before but we have not seen the option dynam Please notice that in this command we are telling MOSES three things Option Description correct to calculate the CGs and the derivatives at each event in the simulation percent to empty the compartment to 0 percent dynam the compartment will be filled dynamically There are many ways to model the ballast water in a compartment The type cor rect will be used for most analyses If you are interested in the other options please review them under the amp compartment command The other methods of modeling the ballast water are so rarely used that they will not be discussed here A word of caution is needed here The placement of the commands amp compartment with the percent and with the dynam options should be placed immediately before the tdom command If there are commands between the amp compart and tdom you run the risk of water being added to the compartments unintentionally The tdom command is the time domain calculations For dynamic ballasting the
172. simply told MOSES to put in a launchway MOSES did not have sufficient information to make an appropriate model There were messages about this in the log file and here are the results For this analysis we are doing stability and we do not care about the stress In later exercises when we are doing a structural analysis we will care more about these reports The next report Restrain Summary we do care about Here is one way we can make sure that the box was placed where we asked it to be placed We can see that PB and SB were placed 42 feet from the bow each is equidistant from the centerline the midpoint between them is on the centerline and they are 20 89 feet from the keel The first two are easy to check on but what about the 20 89 feet If we go to http bentley ultramarine com hdesk tools vessels cbarges cbrg180 htm we see that the depth of the barge is 14 ft the distance from the keel to the deck We told MOSES to put the box 6 896 feet above the keel So we get 14 6 896 20 89 feet For the next several pages we get Righting Arm Results tables The table headings let us know if it is intact or damaged The damaged cases include a line which reads Compartment Flooded are XX to indicate the damaged condition Please notice that all of the roll columns begin with the value 0 Also please notice that table headers include a line that reads Initial Roll X xx Trim X xx deg These initial values are the equil
173. ss 30mm e Place node J0101 15 meters from the bow and 17 5 meters on the starboard side e Place leg with nodes J0101 and J0401 parallel to the barge side shell e The centerline of the leg is 1 5 meters above the barge deck e For the tiedowns use OD 420mm and thickness 25mm e Use 4 tiedowns evenly distributed around each can e For structural analysis assume barge can take tension from tiedowns e Place the barge at 3 2 m draft and 0 57 degree trim e Use the following ballast arrangement name full name full 2p 100 2s 100 3ap 100 3bp 100 3bs 100 4bp 100 Abs 100 5bs 60 5bp 100 6bp 100 6bs 100 8ap 100 8as 100 8c 100 e Use 3D diffraction to calculate the hydrodynamics e Wind Values e For intact stability use 100 knots e For vortex shedding use 80 knots Page 140 e For structural analysis use 90 knots e the environments to be used for calculating accelerations and structural analysis name Hs Tm D 1 7 10 5 F 2 3 8 9 G 1 2 7 0 UAD Jacket _ eR a Ape on julieb A A pS re 5 FIGURE 1 Figure 55 Isometric view of transportation Discussion Many of the project specifications we have seen before There are three new specifi cations to be discussed e The ballast arrangment e Use 3D diffraction to calculate the hydrodynamics e Place leg with nodes J0101 and J0401 parallel to the barge side shell For this exercise a translation from SACS is not needed
174. ssumed to be rigid and the behavior of the structure was considered under the action of 282 basic load cases The structure will be checked for the environments Case Mean Period Sec H 5 0 10 00 S 4 0 11 00 V 6 0 12 00 Each of the above environments are used with the RAO load cases to produce spectral cases These were obtained by first integrating the prod uct of a member load RAO squared times the spectrum then multiplying by a probability factor to obtain the dynamic stress Here the proba bility of the average of the 1 1000th highest values was used to compute the dynamic stress These dynamic stresses are combined with the static stresses to get two load cases for each spectrum and direction These were named LXXXAS and LXXXAC Here the naming convention is that the L in the name is the letter corresponding to the spectrum defined above XXX is the direction and A is a process designator The cases ending with S are the normal ones they are the wind cases plus the dynamic deviation times the sign of the mean This governs most members In some cases however the mean of the member may be slightly in tension and the compression cases will govern Thus the C cases are the S cases minus twice the dynamic deviation To check uplift an additional spectral condition was used LXXXAU These are the mean plus the dynamic deviation A sequential structural solution was performed First the syst
175. st command CONN_DESIGN enters the Connector Design Menu Once inside the Connector Design Menu we are going to create a table of the properties of the catenary mooring line named A Then we are going to create a report of the properties of the mooring system when the barge is moved in the 90 deg heading Please see the manual for the specifics of the command This is the end of the modeling part of this example This is a good place to do Exercise A Preparation for Dynamic Analysis Discussion Now that we are satisfied with out setup we still need a hydrodynamic database environment and an equilibrium position before any dynamic analysis can be per formed The next section has been commented as Frequency Domain and was discussed in previous exercises Now that we have a hydrodynamic database let s get an environment definition and place the vessel at an equilibrium position The next section has been labeled Find Equilibrium The first command defines the environment The second commands tries to find an equilibrium position The environment chosen name is TEST Only a wave environment and time param eters have been defined Please see the amp env command in the manual to see all of the other options available I have specifically written tries to find equilibrium because there is the possibility that MOSES will not find equilibrium You need to keep monitoring the log file and if equilibrium is not found then you need
176. started an initialization of the variable n_shr is performed amp set n_shr simply make the variable n_shr exist This variable is used in the loops When the loops are first started n_shr is empty If it does not exist before it is used it will cause errors Remember for these variables we kept two columns For the variable shr we kept the column for location and the column for the shear value If you review the output report titled Longitudinal Strength Results we have shr 0 29979 5 90241 10 150503 400 29981 The loop that is being used here looks at the values in multiples of 2 Let s look at Page 51 this loop similar to how we looked at the loop in the data file The first time through ppp 1 chg 29979 chg 29979 xval 0 n_shr 0 29979 The second time through ppp 2 che 90241 chg 90241 xval 5 n shr 0 29979 5 90241 The final time through ppp 81 chg 29981 chg 29981 xval 400 n shr 0 29979 5 90241 400 29981 A similar pattern is followed for the variable bmom creating the variable n_ bmom At the conclusion we have changed the sign for shear and bending moment results from the traditional naval architecture approach Now we need to report the values from the structural analysis method and compare them to the traditional naval architecture method To enter the structural post processing menu the command strpost is used To exit the struc
177. t The first line amp tYPe kk kkk k OK k Kk is meant to draw our attention The second line amp type alarm c1 amp info alarm_sensor sc1 reports the value of the sensor This will be either false or true The third line reports the global coordinate location of the point amp type C1 amp point coord C1 g The next set of commands are an if statement therefore we are going to treat as a group amp if amp info alarm_sensor sci amp then amp compartment open_valve c1 percent c1 100 amp endif From two lines above we can see what the value of amp info alarm_sensor scl is We will be able to see if a false or a true we substituted for the middle section of this command If a false is substituted then nothing happens If a true is substituted then the command amp compartment open_valve cl percent cl 100 is executed The manual page for this command can be found at the following link http bentley ultramarine com hdesk ref_man cmp_fill htm amp COMPARTMENT In order for a change in ballast water inside the compartment to occur we first have to tell MOSES the maximum volume of the fluid in the compartment can be The manual page states The change of fluid in the compartment occurs statically and can be observed using amp status compartment The maximum volume of fluid in the compartment is artificailly limited by that specified using the add ballast options
178. t The type of b_cat connects a body to the ground or as I like to think it connects the body to the bottom Also I want to clarify that 4000 ft is the starting length for MOSES We may ask MOSES to change the length depending on the tension horizontal force or another parameter The 4000 ft length can be changed much as in real life the mooring line length can be let out or drawn in Now we define the actual lines a through h There are two lines at each corner Here as with everywhere else if you do not name an item MOSES will provide a name Instead of having MOSES make up a name we are using letters to name them You are free to name them whatever you like There is an eight character limit That is the end of editing the model All of these commands could have been placed in the DAT file I put them here because of habit This separates the body model from the connector model This is because there is normally a need to reposition as was done in this sample with the amp instate command the bodies before the connectors are defined The repositioning happens in the CIF file so the connectors are defined after repositioning the body in the CIF file The next section is commented with Move Anchors Earlier we let the anchor simply fall into the water so that they landed 20 ft horizontally from the vessel Page 85 Figure 37 shows what the mooring system looks like at this point The command amp connector a_tension
179. t a point Reference files ultra hdesk runs samples sea_keep cargo cif cargo dat ultra hdesk runs samples sea_keep rao cif ultra hdesk runs samples data pcomp dat Discussion The command file for cargo cif is very similar to rao cif The files rao cif and rao dat are discussed on the web page http bentley ultramarine com hdesk runs samples sea_keep rao htm It is a good idea to read the entire section on sea keeping that is available on the web http bentley ultramarine com hdesk runs samples sea_keep doc htm The file cargo cif is in the ultra hdesk samples sea_keep directory This CIF file shows how to do a frequency domain motion analysis This is the first of two exercises that deals with motion analysis For this first exercise we introduce the concept of parts In the next exercise the parts will be held together with connectors Let s start by looking at the pcomp dat file In the Basic Stability exercise we used a part but it was not discussed In this file we are again using the cargo barge cbrg180 from the library The new part is under the section labeled add cargo This section begins with the command describe part cargo In MOSES a part is defined within the body coordinate system Here the coordinate system references the barge origin Please recall that for the vessels in the vessel library the origin of the coordinate system is the intersection of the bow the centerline and keel The command amp d
180. t turns on all of the degrees of freedom for that body The results of the next amp equi command show that both the barge and the jacket are now in equilibrium Note that now the barge has a list to starboard RX 0 17 deg and the jacket has a list toward port The same report is repeated with the amp status config command As before we also review the results from the amp status bw command The results in these reports will not include the force of the connectors slings We are NOT expecting the buoyancy force to equal the weight And finally we activate the airtuggers with the command amp connector air active Once we have activated the airtuggers we review the forces on the connectors again and find the force in the boom line is 1184 kips Since our crane capacity is 1000 Page 108 kips we are going to need a larger crane barge However for the current lesson we will assume that the crane is capable of handling the loads Before ending the static analysis section we plot some pictures The three commands that begin with amp picture will save the views starboard bow and top Now we get to talk about the body ZZZGLOBAXES In the starboard view of the system you will see thick green arrows which represent the X and Z axes From the top view you will see the X and Y axes so that the body ZZZGLOBAXES acts as a visual reminder of the global system Sample of sidelift Figure 47
181. t would use However the location of the valve is important to our analysis It would be acceptable to leave the area option out This is the first time we will be defining a compartment The general format is sim ilar to that of defining the outer shell Different options are used when we define the compartment The holes are associated with the compartment as part of the amp describe compartment command As part of the pgen command we assign a permi ability with the option perm and designate its diffraction type as none with the option diftype The rest of the definition should be a review of the pgen command used earlier In the last of the model definition begins again with amp describe body test In this section we are defining sensors at the valve locations One sensor for each valve The manual reference page for sensor definition is at the following link http bentley ultramarine com hdesk ref_man sensor htm amp DESCRIBE SEN SOR The sensor are named with the letter s being added to the point name Just as Page 17 with the hole defintion the point is associate with each sensor Here we use the option signal s_type s_source s_desired s_val s_b s_n And the option limits lim_l lim_u For the first option signal the following is how the values are interpretted s type point s_source cl s_desired s_val value s_b 3rd value sn The tricky part may be figuring out that s desired was le
182. ted In The Part System Weight Buoyancy Center of Gravity Category Factor Factor Weight x v 2 Buoyancy FUEL 1 066 1 666 7 98 76 54 6 66 4 36 6 66 l L_SHIP 1 666 1 666 1575 66 47 34 6 66 3 35 6 66 WEIGHT1 1 068 1 606 2641 21 45 72 6 66 3 05 6 66 WEIGHT2 1 666 1 666 2641 21 45 72 6 66 4 57 6 66 WEIGHT3 1 666 1 666 2641 21 45 72 6 66 6 16 6 66 TOTAL 7766 66 46 08 6 66 4 32 6 66 ii Figure 3 Category Summary Please notice that the table header reads Category Status for Selected Parts For our analysis there is only one body and one part so we do not have to worry about getting confused In later exercises we will be working with several parts so we need to read the table headers carefully to fully understand their contents If you scan the CIF file you will notice that there are titles added first second third in lines 17 22 and 28 In the reports with the title first the barge is not in equilibrium In the reports with the title second ballast water has been added with the amp cmp_bal command and the barge is now in equilibrium The commands amp status b_w hard and amp status compart hard produce the tables titled Buoyancy and Weight for SMIT5 and Compartment Properties in the output file For those with the page title second we have not specified a fill type so the default of CORRECT is used For those with the page title third we have specified the fill ty
183. th the command st_point sea issc 90 10 4 e_period 5 6 7 8 9 followed by report motion This command calculates the statistics of the body motions for a sea with an ISSC distribution in the 90 degree heading to the vessel with a 10 ft significant wave height and a 4 second mean period The option e_period instructs MOSES to consider the additional mean periods listed Again we are placed in the Disposition Menu where we tell MOSES to report the motion statistics report motion and exit the Disposition Menu end In the out file we can review the results of st_point Here we have a report titled MOTION STATISTICS Here the third line of each report reads Maximum Responses Based on a Multiplier of 3 720 This tells us on what statistic the maximum values are based In this case the max ima have a multiplier of 3 72 which corresponds to A1 1000 The multiplier for other values can be readily derived from the derivation of the Rayleigh distribution They are also shown in the document HOW MOSES DEALS WITH TECHNICAL IS SUES which is included in the MOSES distribution hdesk documents include deals pdf We see that motions for the barge increase as the wave period increases For the jacket however we see the motions are mixed For sway the largest motion is 9 seconds For heave and roll the largest response is around 6 seconds What catches our attention is that the maximum dynamic response in sway is 69 ft If you recall
184. the anchor location in the bow lines so that the pretension is 70 kips Change the environment description so that the time step is 0 5 seconds 1 Make a plot of event vs FY TBRG 2 What is the extreme clearance for point MLC Page 91 3 What is the mean of the Z location of the barge 4 Make a plot of event vs force magnitude on mooring line B Page 92 5 4 CALM Mooring Topics e Connection two floating bodies with a flexible connector e Equilbrium of separate bodies within the same analysis Reference files calm cif calm dat Modeling Discussion The reference files are in the samples directory under mooring The reader should be familiar enough with the web page to be able to locate these files and place them in the directory they will be using Most of the commands and the arrangement of the commands have been presented earlier Here we are going to analyse a tanker connected to a buoy via a hawser This would be similar to an offloading scenario The buoy has the spread mooring system is attached to the tanker via a hawser The tanker is allowed to weathervane around the buoy This analysis is considered the second part of the mooring analysis exercises Command file Discussion We will start by discussing the data file Indeed many of the commands are similar The buoy is represented by a structural model made of beam elements The vessel model is a panel model created with pgen The buoy model starts wit
185. the beam of the barge is 170 ft the bottom elevation of the jacket is 96 ft The jacket origin was placed 200 ft starboard of the barge centerline This leaves 69 ft of clearance The report we are reading tells us that there is the possibility of collision Following the motion reports we next report the forces in the connectors The connectors do not belong to a body so it does not matter if the last amp describe body command was for the jacket or for the barge First we get the frequency response for the sling labeled sling1 fr_cforce sling1 Then we get the frequency response for the boom sling fr_cforce boom In the last set of commands we ask for the statistics of the connector forces in the defined sea state This is done in the command st_cforce sea issc 90 10 4 e_period 56789 Like the motions this calculates the statistics of the connector forces for a sea with ISSC distribution in the 90 degree heading to the vessel with a 10 ft Page 111 significant wave height The mean periods of the distribution that will be considered are those listed from 4 to 9 When we review the results of fr_cforce we see that the peak response occurs at 8 seconds This is in the out file table titled Connector Force Response Operators This means that a wave with a mean period of 8 seconds will reinforce the response By reviewing the connector force statistics results of st_cforce we see that the highest force is reported around the
186. the five characters fenb The note is telling us that the fender attachment point on the body barge is located at y 15 85 or 15 85m on the port side This locates the barge attachment point at y 29 35 in the global coordinate system If you take into account the x location of the body barge you will see that the four attachment points on the barge are defined at the same global location as the four attachment points on the tanker This leads us into the connector definition Defining a connector consists of two steps Page 81 first you define the class then you define the connector For the fenders we are going to be using generalized springs which are listed under the Flexible Connector Classes The manual page on flexible connectors can be found at the following link http bentley ultramarine com hdesk ref_man cls_flx htm The format and the use of the command that we are working with is CLASS GSPR SENSE DF 1 SPV 1 AF 1 DF n SPV n AF n fend GSPR compression x 100 2000 y 1 2000 z 1 2000 The name of the class is fend The is part of the name We are defining a compression element with a spring constant K 100 mtons m in the element x direction The maximum allowable force is 2000 mtons In the element y and z direction has a spring constant K 1 mton m and the maximum allowable force is 2000 mtons Basically the element has the x direction as the strong axis which means that we need to be clea
187. ting deck on the Tidmar 251 td mar251 dat file e Take out the tiedowns that are translated with the model elements with class T D e Put the trailing nodes J3304 and J3303 at 100 ft from the bow e Put the bottom of the legs 5 ft above the barge deck e Use tubulars of OD 48 in ID 1 375 in for the cans Page 138 e Use tubulars of OD 36 in ID 1 375 in for the tiedowns e Use the nodes j3107 j3108 j3104 and j3103 for tiedown connections at the deck e The tiedowns should go to the barge deck and shell intersection e The tiedowns should span 11 ft longitudinally between the deck point and the barge touch down point e Use the same env dat for the fatigue data e The barge is to have a draft of 8 ft with a trim 0 57 e Use the same winds and sea spectra The suggested cif and data files for this exercise are found in directory ultra hdesk runs samples install files tow_exer cif tow_exer dat The translated deck file is in the directory ultra hdesk runs samples data file dk_exer dat Page 139 6 2 Using the Orient Option Topics e Orienting the jacket to have one leg parallel to the barge sideshell e Calculating the hydrodynamic database with 3D diffraction Project Specifications e Use the jacket in file quad dat e Use meters and mtons for reporting e Use the Julieb barge e Support the jacket on nodes J0101 J0201 J0301 J0401 J0105 J0205 J0305 J0405 e For the cans use OD 920mm and thickne
188. tramarine com hdesk ref_man install htm The discussion for m_stab cif is located at http bentley ultramarine com hdesk runs samples hystat m_stab htm The file istab uses the automatic installation tools to perform a stability analysis The m stab files also use a macro The m stab files use the stability macros The stability macros allow for more control over the criteria I_STAB Discussion The i_stab files are meant as an introduction to the Automated Installation Tools The full description of the automated installation tools can be found at the second link listed above If you go there you will see the files can be long and detailed For this example we will be setting up the most simple of examples for a stability analysis For this exercise we are really just interested in understanding a few sections of these two files Please read the manual sections that correspond to the sections we discuss here We will be working with the automated installation tools in several of the exercises By reading the manual presentation in sections you will be able to understand all of the tools much easier Let us start with the CIF file At the beginning of the CIF file after the amp device command there are five variables launch transportation loadout upend and lift As implied by the name of the exercise we are really just interested in transportation stability So the only variable that has been set to true is transportation
189. trrtrrtrrtertrrtrrrrrtrrerrtrrcrrtrrrrrrrrrrrrrrs RESTORING FORCE us EXCURSION OF BUOY I Process is DEFAULT Units Are Degrees Meters and M Tons Unless Specified il faenanensense Position Jaena Restoring Force Max Tension Line Min Tension Line Excursion Angle x y FX FY Resultant Tension H Force Ratio Tension H Force Ratio i 6 666 186 66 6 66 6 68 6 8 6 6 6 6 2 3 6 8 6 667 2 3 6 8 6 067 6 562 186 66 8 56 8 08 6 4 8 8 6 4 2 4 8 9 8 007 2 2 8 7 8 006 f 1 123 180 00 1 12 8 00 6 9 8 0 8 9 2 4 1 0 6 667 2 1 6 6 6 666 1 685 186 66 1 68 0 00 1 3 08 0 1 3 2 5 1 1 6 667 2 6 6 5 6 666 2 246 186 66 2 25 8 08 1 7 0 8 1 7 2 6 1 2 6 668 1 9 6 4 6 665 j 2 808 186 66 2 81 8 08 2 8 6 8 2 0 2 7 1 3 6 668 1 9 6 4 6 605 i 3 369 186 66 3 37 8 00 2 2 6 6 2 2 2 8 1 4 0 008 1 9 6 4 6 665 3 931 186 66 3 93 8 08 2 5 6 8 2 5 3 6 1 5 6 668 1 8 6 3 6 605 h 4 493 186 66 4 49 8 08 2 8 0 8 2 8 3 1 1 6 6 669 1 8 6 3 6 605 5 054 180 00 5 05 06 00 3 1 6 6 3 1 3 2 1 7 6 669 1 8 6 3 6 005 hy 5 616 186 66 5 62 86 08 3 7 0 8 3 7 3 4 2 0 6 616 1 8 6 3 6 665 i 6 177 186 66 6 18 8 08 4 4 6 8 4 4 3 8 2 3 6 611 1 8 6 3 6 665 6 739 186 66 6 74 6 00 5 1 6 6 5 1 4 1 2 6 6 612 1 7 6 2 6 605 7 300 186 66 7 30 8 00 5 8 6 6 5 8 4 4 2 9 6 613 1 7 6 2 6 605 7 862 186 66 7 86 8 08 6 5 6 8 6 5 4 8 3 3 6 614 1 7 6 2 6 605 8 424 180 66 8 42 8 08 7 2 0 8 7 2 5 1 3 6 6 615 1 7 6 2 6 605 8 985 186 66 8 99 06 00 8 4 6
190. tudinal location does the shear force cross the zero axis for the wave crest at location 0 0 4 At what longitudinal location does the shear force cross the zero axis for the wave crest at location 200 0 Exercise B The number of stations defined effects the results In the file b_run dat change line 20 which now reads plane O 100 200 300 400 rect 0O 25 100 to plane O 50 100 150 200 250 300 350 400 rect 0O 25 100 Delete the b_run dba directory Then re run the analysis Did the graphs change Page 7 2 2 Basic Stability Topics e Righting arms e Defining weights e Model summary reports Reference files bstab cif bstab dat wcomp cif wcomp dat Discussion The files bstab cif and bstab dat are example files that come with MOSES They are located in the ultra hdesk runs samples hystat directory This assumes that you installed MOSES with the defaults If not the directory is below wherever you installed the ultra directory There is a plethora of information on the website The discussions and exercises hopefully will also provide a good tour through the website The discussion for these two files are located at e http bentley ultramarine com hdesk runs samples hystat bstab htm e http bentley ultramarine com hdesk runs samples hystat wcomp htm After you have read the discussion see if you can answer the following questions Bstab Questions 1 For the Draft 7 ft with a KG 5 5 ft what is the GML for CBRG180
191. tural post processing menu the command end is used The first report generated is the deflections The command joint disp local yes file yes generates the Joint Displacement report in the output file and the top portion of the ppo00001 txt file in the answers directory The command rest detail generates the Restraint Load Detail and the Restraint Envelope Standard reports in the output file The command beam load file yes generates the Beam Load Standard report in the output file and the bottom portion of the ppo00001 txt file in the answers directory The shear and bending moment values in this report are the ones we want to compare to however they are not available in pre formated tabular form We need to issue the bmom_shr command to have them available in the disposition menu so that we can save the values for later comparison After the bmom_shr command we are in the disposition menu Earlier when we were in the disposition menu we saved the value of interest into variables Now we are going to add these values to the ones already there We add these with the command Page 52 add_column input CS X 1 Y 1 X 2 Y 2 When we add our two columns we will input 1 for CS because the first column in this table is distance Which is the same concept as location that we saved I know the first column is distance because of the results of the command vlist a few lines down in the command file In the log fi
192. uctural Element Bargs Nods Nearest the Rocker Pin JACKET SUPPORT CONDITION FOR LAUNCH AFTER TIPPING FIGURE 29 Figure 64 Jacket Support Condition After Tipping As you can see we really need a compromise here We need to combine both methods This is what is done in the Combining Both section LCASE process 0 25 LCASE lleforce 1 2 50 process 30 35 27 40 S_BODY JACKET S_REST amp LWAY SSOLVE NONLINEAR Notice that the output for each structural analysis is similar For the approximate solution only one restraint report is generated Remember for the approximate so lution only the SPRING restraint is used The table summarizes the value of this restraint for the five load cases generated For the other two methods each amp LR element can be a restraint at each time step A separate table is needed to represent the restraints at each time step This concludes the discussion of the native files for launch The following exercise concentrates on understanding the output Exercise A It is a good idea to take the values from the amp status g_Iway table and place them in Page 155 their corresponding location in Figure 64 Exercise B Fill in the table with the values presented in the structural WS Beam Check Standard reports BB tip stands for Better Before Tip method Element Method Case Unity Ratio HOR 0068 Approximate BB Tip Combined VER 0074 Approximate BB Tip Combined
193. vailable for reporting The following is the link to the Page 49 manual page on the set command http bentley ultramarine com hdesk ref_man disp_set htm 4SET_VARIABLE Traditional Results amp E gE iia a Shear j o Moment r a o n 2 5 Z j LN j j Eg i Fo f Fi f A f d Q H a gq n X ol Hap f pe a a ol me gal SE 2 4 i o j j al b f ffa P n f f o j Lo a j u H j j gj N 9 u Y a AN b fN o a T T r T r T T T det o 0 40 80 120 160 200 240 280 320 360 400 Long Location Figure 23 Traditional Shear and Bending Moment Results The comments in the file tell us what is being stored In variable shr we are capturing location and shear values In variable bmom we are capturing location and moment values In varible defl we are capturing location and deflection values In the last comment store the data from columns 1 location 2 shear 3 bending moment and 5 deflections will be saved in the answers directory as a comma separated file file ending in csv The first end takes us out of the disposition menu The second end takes us out of the hydrostatics menu This concludes the traditional naval architecture part of the analysis The structural analysis begins with the comment line structural analysis The first command is necessary although not obvious W
194. ve a general 45 degree pattern On the connector definition we are only specific about which node on the jacket the connector is to attach For the barge end the wild character is used This leaves the connection at the barge end up to MOSES MOSES is going to place the barge end of the connector at 4 ft in the x direction 4 ft in the y direction and 5 ft in the negative z direction From this location it will make a rigid connection to the nearest barge node How MOSES does this is also discussed in the user s manual Please see the following link bentley ultramarine com hdesk ref_man p_conn htm PCONNECT This is all of the model editing we will do Exit the Model Editing menu with the command end_medit In the next set of commands we bring the barge body system tow_brg jacket tiedowns and cans into equilibrium The command amp weight compute instructs MOSES to add a weight positive or negative such that the sum of the forces and Page 124 moments is within the default tolerance The weight will be added at 10 ft height from the keel and the x and y location of the weight will be determined by the moment needed After this command we confirm the system is in equilibrium with the amp equi command The summary of the input consists of pages 1 through 11 The tables presented in the output file pages 2 through 9 are a result of the commands within the Summary Menu We enter this menu with the command amp summary and exit it
195. y a distributed weight When we look at pictures all we will see is the node The weight is at x 0 y 0 and z 0 and the weight is distributed from 0 5 ft to 0 5 ft The distribution was done with the Idist option The only other thing worth noting is that the part cargo is being defined within the body barge coordinate system It is a good idea to run the analysis at this point After running you will also have an answers p_m ans directory In the answers directory you will have the pictures the log and the output file Now we are ready to discuss the CIF file The first new command is amp describe part cargo move 200 We are moving the cargo from the location x 0 to the location x 200 Please note that we did not move it transversely nor vertically When we view pictures we are going to have to look at the keel to find the node belonging to cargo In the log file you will notice that there is a message INFORMATION Part Connectors May Be Incorrect This message appears any time a part is moved via the command file Our analysis does not include connectors between the parts We are going to ignore the message We have seen the amp weight compute command We are familiar with using the hstatic command to enter the Hydrostatics Menu This is the first time we see the moment command Exercise A Here we have a similar structure as with the RARM command we saw in Basic Stability Exercise The moment command doe
196. zy Bentley Sustaining nfrastructure An Introduction to MOSES Spring 2013 Rev C 3 All rights reserved No part of this publication may be reproduced or transmitted in any form or by any means including photocopy and internet distribution without the written permission of Bentley Sys tems 2013 Bentley Systems Contents 1 1 1 Installing MOSES Windows oaa aaa 2 2 Hydrostatic and Lontudinal Strength 4 2 1 Getting Started Exercise oa aa 4 2 2 Basic Stability Soe ee kee ee a 8 2 3 Free Surface Correction ooa aa a 10 2 4 Compartment Ballasting using Valves 16 2 5 Stability Check and KG Allow 30 2 6 Longitudinal Strength eas eo te ee ee RARE SG A OS 39 2 7 Longitudinal Strength Part 2 aa aaa a 43 3 Convert from SACS 56 3 1 Translating from SACS aoaaa a 56 58 4 1 Dynamic Flooding ee a wee eRe a 58 4 2 Basic Frequency Domain Motion 68 5 Connectors 72 5 1 Sling Assemblies aa aa bee a eee ee ew 73 5 2 Modeling a Fender o aaa a 80 5 3 Basic Mooring ooa ee ee ee eae amp A eres 84 5 4 CALM Mooring a aoaaa hee eee eee eed 93 5 5 BICC dss 344 home SPREE RSE Se REE EYES it 101 6 Advanced Exercises 121 6 1 Transportation Analysis 0 22208 122 6 2 Using the Orient Option 226444 lt 2 pede bee os 140 6 3 Launch 244 4 44h Pe ebbant hha ea 64444 24 4 146 T Answers 162 7 1 Getting Started Exercise oao oa a a a a 162

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