A Finite Element Program (FECGS): Post-Processor FEPOST
Contents
1. node n n is the total number of nodes node i is the nodal label Examples 1 Use the following entries to define a line from point X1 Y1 Z1 to X2 Y2 Z2 along which the distribution of selected variables is calculated SEGMENT NUMBER 40 SCALE 1 2 TYPE LINE 50 CHAPTER 3 COMMAND DESCRIPTION 0 0 0 0 0 0 10 0 0 0 0 0 2 Use the following entries to define a elliptic curve centered at point 0 0 0 0 0 0 the two semi axes of ellipse are 15 0 and 10 0 respectively SEGMENT NUMBER 40 SCALE 1 2 TYPE ARC 0 0 0 0 0 0 15 0 10 0 0 0 90 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 3 Use the following entries to define a line formed by the nodes 1 2 3 4 5 6 7 8 9 10 SEGMENT TYPE NODE 10 1 2 3 4 5 6 7 8 9 10 3 10 PATH CALCULATING THE RESULTS ALONG A GIVEN CURVE 51 3 10 3 NORMALIZE Normalizing the coordinates NORMALIZE is Suboption of PATH command for normalizing the coordinates The following parameters are required TYPE Set TYPE CONSTANT the coordinates are normalized by a constant TYPE Jnx x the coordinates are normal ized by Jnx x o TYPE Jav the coordinates are normal ized by average J Jav o TYPE Knii the coordinates are normalized by Knx x o5 referring to the section 3 9 6 for the definition of Jnx x Format Entry If INPUT CONSTANT the following data line is required F Constant Examples 1 Use the following entry to normalize t2. Examples 1 Use the following entries to define a list of variables VARIABLE 11 22 12 E11 E22 E12 MISES 3 10 PATH CALCULATING THE RESULTS ALONG A GIVEN CURVE 49 3 10 2 SEGMENT Defining a curve Command SEGMENT suboption of PATH command defines the curves in which the distri bution of the listed variables is calculated The following parameters are optional NUM Number of segments to be divided By default NUM 20 TYPE Set this parameter equal to curve type TYPE LINE default defining a line between two given points TYPE ARC defining an elliptical curve TYPE NODE defining a list of nodes SCALE Set this parameter equal to a real number q to define a power law bias by default g 1 0 The segment lengths are scaled by 1 q q distribution Format Entry The following data line is required if TYPE LINE 6F X1 Y1 Z1 X2 Y2 Z2 X1 Y1 Z1 define point 1 and X2 Y2 Z2 define point 2 The following data lines are required if TYPE ARC TF X0 YO ZO AO CO T1 T2 Among those X0 YO Z0 defines center of ellipse AO and CO define the two semi axes of ellipse along X and Y axes in the local coordinate system respectively T1 and T2 are angles in degree 0 360 of counterclockwise to define a part of ellipse 9F nll n12 n13 n21 n22 n23 n31 n32 n33 Defining the local coordinate system The following data line is required if TYPE NODE n 1 I n node 1 node 2
3. Jn05 10 1 Use the following entry to select the contour 10 J integral in a 2D analysis Jn10 42 CHAPTER 3 COMMAND DESCRIPTION 3 9 7 TIME LOAD Convert time to related applied load or deformation TIME LOAD suboption of PARAMETER command is used to convert the total time in a FE analysis to the corresponding applied force displacement etc The following parameter isoptional NAME Set this parameter equal to the name of the time load to be given Format Entry The following data line is required A LF STEP K AMAG String STEP is case sensitive K is the STEP number AMAG is the magnitude of applied value in the time load step K Repeat the above line as often as needed to give the more step Examples 1 Use the following entries to convert the total time to the applied load TIME LOAD NAME FORCE STEP 1 100 0 STEP 2 400 0 STEP 3 500 0 3 9 PARAMETER GENERATING A TABULAR LIST 43 3 9 8 T STRESS Evaluating the T stress T STRESS suboption of PARAMETER command is used for evaluating the elastic T stress The details of the formulation for calculating the T stress is given in section This option works for both homogeneous material and bimaterial interfacial crack The following parameters are required RADIUS Set this parameter equal to radius where T stress is going to be calcu lated START ANGLE Set this parameter equal to an angle in degree 0 360 END ANGLE Set this par
4. DEFORM is used to specify a color table In particularly if the model contains several mesh areas corresponding to different materials one may wish to plot the different material regions based on a predefined color table Format Entry The following data line is needed for COLOR TABLE command n 1 I n color 1 color 2 color n n is number of colors and color i is the color identifier defined in the section Examples 1 The following entries are used to specify a color table of 6 colors with the color identifiers 4 6 8 10 12 and 15 The color identifiers have been defined in section 2 4 COLOR TABLE 6 4 6 8 10 12 15 28 CHAPTER 3 COMMAND DESCRIPTION 3 4 EL REMOVE Removing the element from the model The EL REMOVE is used to remove the elements from the model based on a given criterion The command is specially for the application of the local approach based fracture mechanics analysis The following parameters are required VARIABLE Set this parameter equal to identifier of the variables which is used as the criterion for removing elements If a variable in any integration point of an element satisfies the given criterion this element is removed and it will not appear in for examples the deformed mesh plot and the contour plot GT Set this parameter equal to a critical value of the VARI ABLE for removing the element if the defined variable is greater than this values the element will be remov
5. 0 400 0 500 0 18 CHAPTER 3 COMMAND DESCRIPTION 3 1 5 REF LENGTH Drawing a reference scale REF LENGTH Suboption of CONTOUR is used to draw a reference length along the hori zontal direction from left to right in the contour plots The following parameters are required LENGTH Set this parameter equal to the reference length scale COORD Set this parameter equal to the coordinates X Y Z where the reference length is going to be drawn e g COORD X Y Z UNIT Set this parameter equal to the definition of the correspond ing reference length Examples 1 The following entry is used to draw a reference length of 10 mm started at point 10 1 0 0 0 and ended at point 20 1 0 0 0 REF LENGTH LENGTH 10 0 COORD 10 1 0 0 0 UNIT 10 0 mm 2 The following entry is used to draw a reference length of 10 mm started at point 10 1 0 0 0 and ended at point 20 1 0 0 0 which is defined as Ro REF LENGTH LENGTH 10 0 COORD 10 1 0 0 0 UNIT Ro 3 1 CONTOUR DRAWING CONTOUR PLOTS 19 3 1 6 DRAW CRACK Drawing current crack DRAW CRACK command suboption of CONTOUR draws the current crack in the contour plot This option is specified for the crack growth simulation using the cohesive zone model Crack tip is indicated by a line which is perpendicular to the crack surface The following parameter is required ELSET Set this parameter equal to the name of the interface elemen
6. Calculating volume average strain Command EPSav a suboption of PARAMETER command is used for calculating the volume average strains over a given material volume The following parameters are required VARIABLE Set this parameter equal to the name of the variable strain to be averaged A list of available variables are E11 E22 E33 E12 E13 E23 NAME Set this parameter equal to the name of the calculated value Examples 1 Use the following entries to calculate the average strains of E11 and E22 over the entire model EPSav VARIABLE E11 NAME E11av EPSav VARIABLE E22 NAME E22av 3 9 PARAMETER GENERATING A TABULAR LIST 39 3 9 5 SUM EVOL Calculating or summing the material volume Command SUM EVOL a suboption of PARAMETER command is used for calculating or summing the material volume defined by element sets The following parameters are optional ELSET Set this parameter equal to the name of the element set in which material volume is calculated By default FEPOST calculates the whole material volume DEFORM Set this parameter equal to YES if material volume has to calculate in the deformed configuration RECORD Set this parameter equal to YES if element volume has been recorded Otherwise FEPOST will calculate element volume by itself NAME Set this parameter equal to the name of the calculated value to be appear in the tabular list The default is NAME TEVOL Format Entry The following data
7. DRAWING CONTOUR PLOTS 15 3 1 2 HISTORY Selecting time increments HISTORY suboption of CONTOUR is used to specify the time increments to be plotted By default all the time increments recorded are plotted Format Entry The following data lines are needed if the HISTORY suboption is used For step increment base A 3I STEP K INC1 INC2 STEP is case sensitive K Step num ber INCI first incremental number INC2 last incremental number FEPOST draws all the increments between INC1 and INC2 at step K or in crack extension base A I nF Da n Da 1 Da 2 Da n Here Da is case sensitive n is number crack extension to be selected Da i is ith selected crack extension Examples 1 Use the following entries to draw contour plot in the corresponding time increments step 1 all increments within increments 5 and 100 step 2 increment 50 and step 3 increment 100 HISTORY STEP 1 5 100 STEP 2 50 50 STEP 3 100 100 2 Use the following entries to draw contour plot for the time increment corresponding to the crack extensions at or about at 0 0 1 0 2 0 4 0 and 6 0 HISTORY Da 5 0 0 1 0 2 0 4 0 6 0 16 CHAPTER 3 COMMAND DESCRIPTION 3 1 3 NORMALIZE Normalizing the coordinates Command NORMALIZE suboption of CONTOUR command is used for normalizing the coordinates in the contour plot The following parameter is required CONSTANT Set this paramete
8. LEVEL 8 ELSET E0000001 2 Use the following entry to draw the contour plot in the deformed configuration with actual displacement contours are filled element boundaries are not plotted there are 8 contour levels contour plot is forced on a single contour value per element 3 1 CONTOUR DRAWING CONTOUR PLOTS 13 CONTOUR OUTPUT MPL QUILT ON MAG 1 0 SHADED YES LEVEL 8 ELSET E0000001 14 CHAPTER 3 COMMAND DESCRIPTION 3 1 1 DETAIL Defining a part of the model Command DETAIL suboption of CONTOUR is used to specify a part of the model to be plotted The DETAIL specification only affects the current contour plot By default the entire model is plotted The following parameters are optional ELSET Set this parameter equal to a element set name defining the elements to be included in the detail Format Entry The following data line is needed if the ELSET parameter is omitted 6F X1 Y1 Z1 X2 Y2 Z2 Here X1 Y1 Z1 define the coordinates of minimum model space bounds of the part of the model to be plotted and X2 Y2 Z2 define the coordinates of maximum model space bounds of the part of the model to be plotted Examples 1 Use the following entry to creat a part of the model defined by element set E0000001 DETAIL ELSET E0000001 2 Use the following entries to define a part of the model bounded by 0 0 0 0 0 0 and 10 0 10 0 0 0 DETAIL 0 0 0 0 0 0 10 0 10 0 0 0 3 1 CONTOUR
9. a near crack tip region of an actual specimen and loading The second term on the right hand side of Eq 5 1 is the first singular stress term in the Williams eigen expansion In FEPOST the 7 stress is calculated as follows py VENT K T S T K r 0 4 faa 0 5 2 ET Y oO m zt 5 2 Alternatively T can also be obtained by d i spec i spec Kr D D T o ejl fra 0 fyl 5 3 60 CHAPTER 5 QUANTITY DEFINITIONS 5 2 The Q stress The definition of the Q stress is given as follows Spec gref Q u 5 4 Oo 5 39 THE WEAKEST LINK MODEL 61 5 3 The Weakest link model Here only the formulations used are listed the detailed explanation and interpretation are not documented The weakest link statistics adopted is jatean v T o 8 as 5 5 The total failure probability is thus 1 exp f lv f sss 5 6 Using three parameter Weibull distribution IA o S dS y FN 5 7 then one has p 1 exp li E ver 5 8 or In 1 4 mmy fr a 5 9 FEPOST calculates the volume integration shown in the right hand side of the above equa tions 5 8 and 5 9
10. data lines are required DOFN NODE Label 2I Degree of freedom Nodal label Repeat the above line as often as needed to give the more points Examples 1 Use the following entries to calculate the nodal displacement U1 at the point 100 0 100 0 0 0 and U2 at the point 0 0 100 0 0 0 PDIS INPUT COORD NAME LOAD 1 100 0 100 0 0 0 2 0 0 100 0 0 0 3 9 PARAMETER GENERATING A TABULAR LIST 35 2 Use the following entries to calculate the nodal displacement U1 for node 100 U2 for node 100 and U2 for node 200 PDIS INPUT NODE NAME LOAD 1 100 2 100 2 200 36 CHAPTER 3 COMMAND DESCRIPTION 3 9 2 PFORCE Calculating reaction force Command PFORCE suboption of PARAMETER command is used to sum the nodal reac tion force at a given degree of freedom for a defined group of nodes The following parameters are required DOFN Set this parameter equal to the degree of freedom NAME Set this parameter equal to the name of the resulted reaction force to be given INPUT Set this parameter equal to POLYGON or NODE for defining a node group Format Entry The following data line is required If INPUT POLYGON enter the following data line to define a group of nodes F X1 Y1 Z1 X2 Y2 Z2 Defining the coordinates of minimum model space bounds X1 Y1 Z1 and the coordinates of maximum model space bounds X2 Y2 Z2 All the nodes within the defined region are included in the group If INPUT NODE ent
11. file 6 CHAPTER 1 GENERAL FEATURES For example suposse that there five output files test1 fil test2 fil test3 fil test4 fil and test5 fil in the current directory To execute FEPOST enter fepost The system will respond with FEPOST Release 1 0 Automatic sreaching output files fil The filenames with extension of fil are 1 test1 fil 2 test2 fil 3 test3 fil 4 test4 fil 5 test fil More than one files are found by program Enter a file identifier Enter the file identifier listed for example 4 FEPOST will inquire its input file test4 post If there is no test4 post existed the program prompts ENTER FILENAME OF INPUT DATA and waiting for the FEPOST input file Chapter 2 INPUT OUTPUT AND PLOT FILES 2 1 2 2 FEPOST input file FECGS ABAQUS OUTPUT FILES An output file from an analysis run must be avail able to provide the model geometry and solution data base from which the FEPOST output will be extracted By default this file name will be used as FEPOST output file name FEPOST INPUT FILES A FEPOST input file should be provided which involves all the commands related parameters and the required valuesto be executed FEPOST output file ERROR FILE An error file is generated with FEPOST output file and attached string perr if there are any errors during FEPOST is executed FEPOST OUTPUT FILE Echo the FEPOST commands the
12. filename is the FEPOST output file name with attached string _pout INFORMATION FILE Writing the resulted information during executing FEPOST the filename is the FEPOST output file name with attached string _pinf JOURNAL FILE Writing the information of execution of FEPOST for examples exe cuted subroutines and CPU time needed the filename is the FEPOST output file name with attached string _pjul NEUTRAL PLOT FILE Save the resulted device independent plot file The plot file extension is mpl with a filename matching that of the output file name CHAPTER 2 INPUT OUTPUT AND PLOT FILES e PATH DATA FILES The results along a given line through the model using the PATH COMMAND for example the stress distribution along a line The file name is output file name with attached string _pathx x the last two characters are the number of PATH command in the form of two digits eg path01 for the first PATH _path02 for the second PATH and so on e PROFILE FILES Resulting profile data using PROFILE command the filename is the output file name with attached string _pprox x the last two characters are the number of PROFILE command in the form of two digits as that define in PATH DATA FILES e TABLE RESULTS FILES A table generated by command PARAMETER the filename is FEPOST output file name with attached string _petm01 2 3 FEPOST PLOT FILE GRAPHIC DISPLAY AND TRANSLATION 9 2 3 FEPOST plot file graphic display an
13. the commands should be given in capitals The command and its related parameters should be given in one line Parameter values are entered with the sign for example VARIABLE MISES Some parameters require two or more values Enter the values grouped by parentheses for example COORDINATES 1 0 1 0 Command name and parameters may be abbreviated on input one must give enough character to make the entry unique in context e g VAR VARIABLES and COORD COORDINATES Some commands require lines of data to be entered All entries are free format with comma or blanks as the separators In this manual the type of data required is indicated by A for a character string F for a floating point number and I for an integer Any line that begins with is treated as a comment line All commands and related inputs are reported in the post output file pout 1 3 Definition of the coordinate system In FEPOST a fixed rectangular Cartesian coordinate system with axes x i 1 2 3 is used system 1 4 Executing FEPOST FEPOST is executed by directly entering fepost The program will automatically looking for the FECGS or ABAQUS results output files fil and displays the files in a list Enter the corre sponding number to indicate files to be processed Then FEPOST will inquire the default input file with extension post If there is no default input file the program will waiting for an input
14. A Finite Element Program FECGS Post Processor FEPOST User s Manual Version 1 0 GUOYU LIN GKSS FORSCHUNGSZENTRUM GEESTHACHT GMBH MAX PLANCK STR D 21502 GEESTHACHT GERMANY July 1997 PREFACE FECGS is a finite element program system hereafter program which includes an implicit FE code for stress analysis and crack growth simulation using micromechanical models e g the cohesive zone model and the Gurson model a pre processor FEMESH and a post processor FEPOST The program is specially developed for the purpose of fracture mechanics analysis However the applicability of the program is rather general The program is for academic and research purpose only The program is provided as is without express or implied warranty The author assumes no responsibility for any errors that may appear using any part of the program However any comments suggestions and bug re ports are appreciated FEPOST is also able to access ABAQUS result file fil This manual provides the basic reference document for FEPOST Point of contact Guoyu Lin Institute of Materials Research GKSS Research Center D 21502 Geesthacht Germany Tel 49 4152 872539 Fax 49 4152 872534 E mail guoyu lin gkss de Contents 1 GENERAL FEATURES 1 1 Introduction 2 2 ll eee L 12 Command entry 1 3 Definition of the coordinate system a a 14 Executing FEPOST sss ee 2 INPUT OUTPUT AND PLOT FILES 2 1 FEPOST input fil
15. Drawing the cohesive zone in the contour plot command DRAW CZM suboption of CONTOUR draws the currently active cohesive zone in the contour plot This option is specified for the crack growth simulation using the cohesive zone model The following parameter is required ELSET Set this parameter equal to the name of the interface element set which is used for the crack growth simulation The following parameter is optional COLOR Set this parameter equal to the color identifier which is used to draw the cohesive zone see section for definition of the color identifiers By default the color is defined by the program Examples 1 The following entry is used to draw the current cohesive zone DRAW CZM ELSET CZMELE COLOR 4 22 CHAPTER 3 COMMAND DESCRIPTION 3 2 CRACK Calculating the crack extension The CRACK command is used to calculate the crack extension from the model based on a given criterion A reference point is first defined The crack extension is calculated as the maximum distance from reference point to the point of farest element node of the failed ele ments These failed elements should be connected each other such that they form an open crack The following parameters are required VARIABLE Set this parameter equal to name of the variable which is used as the criterion for removing elements for example VAR SDV2 If the value of the variable at any integration point of an element satisfies the giv
16. TOUR draws the contour plots The current version is available only for two dimensional problems The following parameters are required OUTPUT Set this parameter equal to MPL for generating a neutral plot file VARIABLE Set this parameter equal to the name of variable to be con toured e g VAR 822 The following parameters are optional UNDEFORM Set this parameter equal to YES for drawing the contour in undeformed configuration The default is OFF QUILT Set QUILT ON to force a single contour value per ele ment for shaded filled contour plots without interpola tion The default is OFF SHADED Set this parameter equal to YES to draw a shaded filled contour plot The default is NO LEVEL The number of contour levels T he default is 10 MAGNIFICATION Magnification factor to be applied to the displacements of the model for display The default is 0 0 no magnification EL PLOT Set EL PLOT NO to suspend drawing the element bound ary in the contour plots By default EL PLOT YES ELSET Set this parameter equal to the name of element set in which the contour plot is generated By default the entire model is drawn Examples 1 Use the following entry to draw the contour plot in the element set E0000001 contours are plotted in the undeformed model and filled with corresponding colors element boundaries are not plotted number of contour levels is 8 CONTOUR OUTPUT MPL UNDEFORM YES EL PLOT NO SHADED YES
17. ameter equal to an angle in degree 0 360 Radius start angle and end angle define a part of circle to evaluate the 7 stress NUM Number of points to be used to calculate the T stress KI Set this parameter equal to Jnx x Format Entry The following data line is required 4F El Pol E2 Po2 Ei and Poi are a pair of Young s mod ulus and Poisson s ratio used for calculating the K from J integral For the homogeneous material only first pair is needed whereas four numbers are need for a bimaterial interface crack Examples 1 Use the following entry to conduct T stress calculation along a given circle of radius 1 0 from 0 to 90 T STRESS RADIUS 1 0 START ANGLE 0 END ANGLE 90 90000 0 0 3 90000 0 0 3 44 CHAPTER 3 COMMAND DESCRIPTION 3 9 9 Q STRESS Evaluating the Q stress at a given point Q STRESS suboption of PARAMETER command is used for evaluating the Q stress at a given point defined by coordinates X Y Z This option is currently not yet available The details of the formulation for calculating the Q stress is given in section The following parameters are required COORD Set this parameter equal to the normalized coordinates X Y Z where Q stress to be calculated for example COORD 0 0 2 0 0 0 J NORMALIZE Set this parameter equal to the selected J integral for normalizing the coordinates referring section 3 9 6 for the selection of J integral YIELD Set this parameter equal to t
18. ated by the FE analysis The following parameter is required SIGMA Set this parameter equal to the reference value for normal izing the stresses The following parameters are optional YOUNG Set this parameter equal to Young s modulus EPS Set this parameter equal to reference strain for normaliz ing the strains The default value is SIGMA YOUNG if YOUNG is given otherwise 1 0 ELSET Set this parameter equal to element set name in which the stresses and strains will be normalized The default is the whole model Examples 1 Use the following entry to normalize the stresses and strains in the element set E0000001 The stresses are normalized by 300 0 and the strains are normalized by 0 00333 300 90000 0 NORMALIZE SIGMA 300 0 YOUNG 90000 0 ELSET E0000001 2 Use the following entry to normalize the stresses and strains in the whole model The stresses are normalized by 300 0 and the strains are normalized by 0 02 NORMALIZE SIGMA 300 0 EPS 0 02 3 Use the following entries to normalize the stresses in the element sets E0000001 E0000002 and E0000003 The stresses are normalized by 300 0 in the element set E0000001 400 0 in the element set E0000002 and 500 0 in the element set E0000003 NORMALIZE SIGMA 300 0 ELSET E0000001 NORMALIZE SIGMA 400 0 ELSET E0000002 NORMALIZE SIGMA 500 0 ELSET E0000003 32 CHAPTER 3 COMMAND DESCRIPTION 3 8 OUTPUT Defining the output file name The OUTPUT command define
19. coordinates 100 0 100 0 0 0 and 0 0 100 0 0 0 S11 INPUT COORD NAME S11 100 0 100 0 0 0 46 CHAPTER 3 COMMAND DESCRIPTION 0 0 100 0 0 0 2 Use the following entries to calculate the stress component S11 at gauss points 1 and 2 of element 100 S11 INPUT GAUSS NAME S11 100 1 100 2 3 10 PATH CALCULATING THE RESULTS ALONG A GIVEN CURVE 47 3 10 PATH Calculating the results along a given curve The PATH command is used to evaluate the distribution of the required variables along a given line or curve The following parameters are optional ELSET OUTPUT Set this parameter equal to the element set name in which the distribu tion of given variables is calculated The default is the whole model Set this parameter equal to HISTORY the distribution of a given vari able along the given curve for the selected time increments is written in a result table By default FEPOST writes the results of the selected variables for each time increment selected The following suboption commands are required VARIABLE SEGMENT 48 CHAPTER 3 COMMAND DESCRIPTION 3 10 1 VARIABLE Selecting output variables VARIABLE suboption of PATH command defines the solution variables such as the stresses and strains to be calculated Format Entry The following data line is required A Give a list of variable names to be calculated If parameter OUTPUT HISTORY is given in PATH enter only one variable name
20. d translation FEPOST generates a device independent graphic file the neutral plot file The data format of the neutral file is according to ABAQUS POST The neutral plot file mpl is a binary file It contains plot commands in a device independent format which can be converted into device specific commands by the device driver The available device drivers are x11 displaying in X window from IBM RISC 6000 ps translating to postscript and pft translating to Mac ProFit with a special ProFit program to draw the plot The FEPOST neutral plot files are also accessible for the ABAQUS device drivers 10 CHAPTER 2 INPUT OUTPUT AND PLOT FILES 2 4 Color definition Valid color definition in FEPOST using color identifiers range from 0 to 15 The color names associated with these identifiers and their color spectrum definitions are 0 Black 0 for all colors 1 White 100 for all colors 2 Grey gray 60 for all colors 3 Blue 100 blue 4 Medium blue 100 blue 60 green 5 Sky blue 100 blue 80 green 6 Cyan 100 blue 90 green T Aqua 10096 green 8096 blue 8 Spring green 10096 green 5596 blue 9 Green 100 green 10 Chartreuse 10096 green 7096 red 11 Yellow 10096 green 10096 red 12 Gold 10096 red 8596 green 13 Dark gold 10096 red 7096 green 14 Orange 10096 red 5096 green 15 Red 10096 red Chapter 3 COMMAND DESCRIPTION 12 CHAPTER 3 COMMAND DESCRIPTION 3 31 CONTOUR Drawing contour plots The command CON
21. e 2 2l RR s 2 0 FEPOST output file ss ssa se caase saa karokra du a ka e G 2 3 FEPOST plot file graphic display and translation 2 4 Color definition 2 2 ee 3 OMMAND DESCRIPTION MALS a SRSA E We S RADAR eRe oo 3 1 1 DETAIL Defining a part of the model Tc x a ILI 3 1 4 LEVEL Defining the contour level enn khu GRR SE od qoa 3 1 66 DRAW CRACK Drawing current crack lll 3 1 7 DRAW CZM Drawing the cohesive zone in the contour plot PTT 3 3 DEFORM Drawing the deformed mesh 00 000008 3 3 1 DETAIL Creating a part of the model 2o rk 3 8 2 HISTORY Selecting the time increments ORAS UR INEO HU IR UIROS 3 4 EL REMOVE Removing the element from the model Ls 3 5 END POST End command input oom ow Ww Oo N NN A 5 CONTENTS 3 6 INT VAR Defining the variables for interpolation 30 3 7 NORMALIZE Normalizing the stresses and strains 31 Lr 32 3 9 PARAMETER Generating a tabularlist 2l 33 3 9 1 PDIS Calculating displacement at a given point s 34 3 9 2 PFORCE Calculating reaction force llle 36 3 9 3 SIGav Calculating volume average stresses ln 37 3 9 4 EPSav Calculating volume average strain 38 2 39 3 9 86 Jnxx xx Selecting the J integral 22 4 n
22. e model DETAIL suboption of DEFORM is used to specify a part of the model to be plotted The DETAIL specification only affects the current deformed plot By default the entire model is plotted The following parameter is optional ELSET Set this parameter equal to a element set name defining the elements to be included in the detail Format Entry The following data line is needed if ELSET parameter is omitted 6F X1 Y1 Z1 X2 Y2 Z2 Here X1 Y1 Z1 define the coordinates of minimum model space bounds of the part of the model to be plotted and X2 Y2 Z2 define the coordinates of maximum model space bounds of the part of the model to be plotted Examples 1 Use the following entry to creat a part of the model defined ny element set E0000001 DETAIL ELSET E0000001 2 Use the following entries to define a part of the model bounded by 0 0 0 0 0 0 and 10 0 10 0 0 0 DETAIL 0 0 0 0 0 0 10 0 10 0 0 0 26 CHAPTER 3 COMMAND DESCRIPTION 3 3 2 HISTORY Selecting the time increments Command HISTORY a suboption of DEFORM is used to specify the time increments to be plotted By default all the time increments recorded are plotted Referring to section for the details of explanation of the command the definition of parameters and its required values and the examples 3 8 DEFORM DRAWING THE DEFORMED MESH 27 3 3 8 COLOR TABLE Defining a color table Command COLOR TABLE a suboption of
23. ed The following parameter is optional ELSET Set this parameter equal to element set name in which the elements may be removed The default is the whole model Examples 1 Use the following entry to conduct element remove in the element set E0000001 If the vari able SDV2 in any gauss point of an element is greater than 0 10 this element will be removed EL REMOVE VARIABLE SDV2 GT 0 10 ELSET E0000001 2 Use the following entry to conduct element removing in the whole model EL REMOVE VARIABLE SDV2 GT 0 10 3 5 END POST END COMMAND INPUT 3 5 END POST End command input This command is used to end the command input in FEPOST 29 30 CHAPTER 3 COMMAND DESCRIPTION 3 6 INT VAR Defining the variables for interpolation The command INT VAR defines the variables to be interpolated from element gauss integration points to the element nodes so that the commands such as CONTOUR PATH can be conducted Format Entry The following data line is needed for command INT VARIABLE A Given a list of variables to be interpolated the variables are separated by comma or blanks Examples 1 The following entries are used to conduct interpolation of the variables S11 22 S12 and SDVI INT VAR S11 S22 12 SDV1 3 7 NORMALIZE NORMALIZING THE STRESSES AND STRAINS 31 3 7 NORMALIZE Normalizing the stresses and strains The NORMALIZE is used to normalize the stresses and strains cre
24. en criterion this element is defined to be failed GT Set this parameter equal to the critical value of the VARI ABLE for defining the failure elements If the variable is greater than this value the element is failed The following parameters are optional ELSET Set this parameter equal to element set name in which the elements may be removed The default is the whole model INPUT Set INPUT COORD reference point for calculating the crack extension is given by the coordinates IN PUT NODE reference point is defined as a finite element node If INPUT parameter is omitted the reference point is defined by the coordinates 0 0 0 0 0 0 Format Entry The following data line is need if INPUT parameter is specified For the case of INPUT COORD 3F X Y Z The coordinates of the reference point Or for the case of INPUT NODE I NODE Nodal label of the reference point Examples 3 2 CRACK CALCULATING THE CRACK EXTENSION 23 1 Use the following entries to calculate crack extension in the element set E0000001 If the variable SDV2 is great than 0 10 this element is failed T he crack extension is calculated as the maximum distance from reference point 0 0 1 0 0 0 to the point of farest element node in the failed elements CRACK INPUT COORD VARIABLE SDV2 GT 0 10 ELSET E0000001 0 0 1 0 0 0 2 The following entries are used to calculate crack extension in the element set E0000001 If the variable SDV2 is great t
25. er the following data line to define a group of nodes n 1 I n Node 1 node 2 node n n is the number of nodes to be included node i is the nodal label Examples 1 Use the following entries to calculate the nodal reaction force in the Y direction resulted from the node group wthin the given polygon The calculated reaction force is named LOAD PFORCE DOFN 2 INPUT POLYGON NAME LOAD 0 0 0 0 0 0 100 100 0 0 0 2 The following entries are used to sum the nodal reaction force in the Y direction from 5 nodes 100 200 400 600 800 The calculated reaction force is named LOAD PFORCE DOFN 2 INPUT NODE NAME LOAD 5 100 200 400 600 800 3 9 PARAMETER GENERATING A TABULAR LIST 37 3 9 3 SIGav Calculating volume average stresses Command SIGav a suboption of PARAMETER command is used for calculating the volume average stresses over a given material volume The following parameters are required VARIABLE Set this parameter equal to the name of the variable stress components to be averaged A list of available variables are S11 22 33 812 S13 23 NAME Set this parameter equal to the name of the calculated value Examples 1 Use the following entries to calculate the average stresses of S11 and 22 over the entire model the resulted values are named S11av and S22av SIGav VARIABLE S11 NAME S11av SIGav VARIABLE S22 NAME S22av 38 CHAPTER 3 COMMAND DESCRIPTION 3 9 4 EPSav
26. h 41 3 9 7 TIME LOAD Convert time to related applied load or deformation 42 3 9 8 T STRESS Evaluating the T stres llle 43 3 9 9 Q STRESS Evaluating the Q stress at a given point 44 3 9 10 VARIABLE S11 22 SDVI1 Calculating the solution variables 45 IT 4T TTE 48 naL Ge es Ge E 49 eee aa duet 51 RT 52 3 11 PLOT MESH Drawing the FE mesh 0 200000 eae 53 Di ip era di See Oe ded 55 P ane we te re 56 LIST OF VARIABLES AND ELEMENT TYPES 57 41 Variable identifiers aa 57 42 Element lists les 57 QUANTITY DEFINITIONS 59 Bil The f stress soos s E ro ok Y nom a ae a ee a ee ae ow 59 ae ba kh Bg eh 60 5 3 The Weakest link model Chapter 1 GENERAL FEATURES 1 1 Introduction FEPOST is part of finite element program system FECGS for the purpose of post processing the results files FEPOST is executed uninteractively by providing a file of commands The present version is available for the IBM workstation RISC 6000 The main input of the program is a file which indicates the options required and gives the data associated with those options Current version of FEPOST is also able to process the output file fil from a finite element analysis run by ABAQUS using the commands NODE FILE and EL FILE FEPOST deals only with nodal variables provided by a FE analysis For the element variables FEPOST
27. han 0 10 this element is failed The crack extension is calculated as the maximum distance from reference point node 10 in the model to the point of farest element node in the failed elements CRACK INPUT NODE VARIABLE SDV2 GT 0 10 ELSET E0000001 10 24 CHAPTER 3 COMMAND DESCRIPTION 3 3 DEFORM Drawing the deformed mesh The command DEFORM draws the deformed configuration In the current version this option is available only for two dimensional problems The following parameter is required OUTPUT Set this parameter equal to MPL for generating a neutral plot file The following parameters are optional ELSET BOUND Set this parameter equal to YES for drawing element set boundaries This parameter is specially for the analysis in volving several material regions UNDEFORM Set this parameter equal to YES for drawing also the unde formed mesh The default is No MAGNIFICATION Set this parameter equal to displacement magnification fac tor for the deformed shape The default value is 1 0 Examples 1 Use the following entry to draw the deformed and undeformed meshes the part of the model to be plotted is defined by the element set E0000001 DEFORM OUTPUT MPL UNDEFORM YES 2 Use the following entry to draw the deformed mesh of the entire model Element set bound aries are plotted also DEFORM OUTPUT MPL ELSET BOUND YES 3 8 DEFORM DRAWING THE DEFORMED MESH 25 3 3 1 DETAIL Creating a part of th
28. he coordinates by Jn11 o NORMALIZE TYPE Jn11 2 Use the following entry to normalize the coordinates by a constant 100 0 NORMALIZE TYPE CONSTANT 100 0 52 CHAPTER 3 COMMAND DESCRIPTION 3 10 4 HISTORY Selecting time increments Command HISTORY suboption of PATH is used to specify a time step to be plotted By default all the time increment recorded are plotted Format Entry The following data lines are needed if HISTORY command is used A 2I STEP K INC String STEP is case sensitive K is the step number INC is the increment number IF INC 0 all the increments in the step K recorded are included IF K 0 all the steps recorded are selected Repeat the above line as often as needed to give the more time increments Examples 1 Use the following entries to select the corresponding time increments HISTORY STEP 1 5 STEP 2 50 STEP 3 100 3 11 PLOT MESH DRAWING THE FE MESH 53 3 11 PLOT MESH Drawing the FE mesh The PLOT MESH command is used to draw the finite element mesh In the current version this option is only available for drawing 2D meshes The following parameter is required OUTPUT Set this parameter equal to MPL for generating the neutral plot file The following options may be needed if one wants to draw the different element sets in different colors ELSET Format Entry The following data line is needed if ELSET option is required A The element set names
29. he reference stress co for normalizing the coordinates J ao Examples 1 Use the following entry to conduct Q stress calculation at a normalized point 2 0 0 0 0 0 Q STRESS COORD 2 0 0 0 0 0 YIELD 300 0 J NOR Jn10 3 9 PARAMETER GENERATING A TABULAR LIST 45 3 9 10 VARIABLE S11 S22 SDV1 Calculating the solution variables VARIABLE Suboption of PARAMETER command is used for evaluating the value of this variable at given point The variable can be any of stress components strain components and state solution variables from FECGS or ABAQUS The available variables are listed in section For example at a given coordinates X Y Z or a given gauss intergration point The following parameters are required INPUT Set INPUT COORD point for calculating the variable is given by the coordinates INPUT GAUSS point is defined as a element gauss point NAME Set this parameter equal to the name of the quantity to be calculated Format Entry If INPUT COORD the following data line is required 3F X Y Z The coordinates where VARIABLE is calculated Repeat the above line as often as needed to give the more points Format Entry If INPUT GAUSS the following data line is required 2I Enter element number Gauss integration number Repeat the above line as often as needed to give the more points Examples 1 Use the following entries to calculate the stress component S11 for the points given by the
30. line is required if material volume include several element sets nA ELSET1 ELSET2 ELSETn Enter all the element set names Each line can have maximum 8 element sets Repeat the above line as often as needed to enter more element sets Examples 1 Use the following entry to calculate the material volume of the element set E1 SUM EVOL ELSET E1 NAME EVOL1 DEFORM YES 2 Use the following entry to calculate the whole material volume SUM EVOL RECORD YES 3 Use the following entry to calculate the whole material volume SUM EVOL NAME EVOL 40 CHAPTER 3 COMMAND DESCRIPTION 4 Use the following entries to calculate the material volume consisting of the element set E1 and E2 SUM EVOL NAME EVOL12 E1 E2 3 9 PARAMETER GENERATING A TABULAR LIST 41 3 9 6 Jnxx xx Selecting the J integral Command Jnx x x x suboption of PARAMETER command is used to select the J integral at the given position and contour for a 3D fracture analysis and a given contour for 2D analysis The first two characters x x are used to define the position of the J integral to be selected in a 3D analysis and the second x x are used to define the contour number of the J integral to be selected at that position For the 2D analysis the command is Jnx x or Jn01 xx and xx indicates the contour number of J integral to be selected Examples 1 Use the following entries to select the J integral in a 3D analysis Jn01 10
31. r equal to the value to normalize the coor dinates in the model Examples 1 Use the following entry to normalize the coordinates by 100 0 NORMALIZE CONSTANT 100 0 3 1 CONTOUR DRAWING CONTOUR PLOTS 17 3 1 4 LEVEL Defining the contour level Command LEVEL suboptions of CONTOUR command is used to define the contour level of the variable to be contoured The contour levels are uniformly distributed according to the number of contour levels or may be entered individually By default the first contour level is taken as minimum value of variable plus 196 of difference between maximum and minimum values the last contour level is taken as minimum value of variable plus 90 of difference between maximum and minimum values The following parameters are optional MINIMUM Set this parameter equal to the value of the minimum con tour level in contour plot The default is the actual minimum value MAXIMUM Set this parameter equal to the value of the maximum con tour level in contour plot The default is the actual maxi mum value Format Entry The following data line is required if both parameters MINIMUM and MAXIMUM are omitted I nF n level 1 level 2 level n n is the number of contour levels Examples 1 Use the following entry to define the minimum and maximum contour levels LEVEL MIN 100 0 MAX 300 2 Use the following entries to define the contour levels LEVEL 5 100 0 200 0 300
32. s a FEPOST output filename The default is the output file name from FECGS ABAQUS without extension fil The following parameteris required FILE Set this parameter equal to the name of the FEPOST output file Examples 1 The following entry defines a FEPOST output filename blabla OUTPUT FILE blabla 3 9 PARAMETER GENERATING A TABULAR LIST 33 3 9 PARAMETER Generating a tabular list The PARAMETER is used to generate a table of variables for the time increments recorded in the FE analysis Following commands are suboption of PARAMETER PDIS PFORCE SIGav EPSav SUM EVOL nx x Xx TIME LOAD T STRESS Q STRESS VARIABLE S11 S22 SDV1 V AVERAGE Those command lines shall be entered after PARAMETER 34 CHAPTER 3 COMMAND DESCRIPTION 3 9 1 PDIS Calculating displacement at a given point Command PDIS suboption of PARAMETER command for evaluating the displacement at a defined degree of freedom for a given point The following parameters are required INPUT Set INPUT COORD point for calculating the displace ment is given by the coordinates INPUT NODE point is defined as a finite element node NAME Set this parameter equal to the name of the displacement for example NAME CTOD Format Entry If INPUT COORD the following data lines are required I 3F Degree of freedom X Y Z Repeat the above line as often as needed to give the more points If INPUT NODE the following
33. t set which is used for the crack growth simulation The following parameters are optional DIRECTION Set this parameter equal to the crack growth direction indi cated by X or Y or Z By default DIR X TIPONLY Set this parameter equal to YES for drawing crack tip only the defaul is TIPONLY NO COLOR Set this parameter equal to the color identifier which is used to draw the crack see section 2 4 for definition of the color identifiers By default the color is defined by the program Format Entry The following data line is required for this option 6F X1 Y1 Z1 X2 Y2 Z2 These six real numbers are used to draw a line from point X1 Y1 Z1 to point X2 Y2 Z2 for indicting the crack tip This line will be moved with crack growth IF suboption NORMALIZE is used Xi Yi Zi shall be the normalized value Examples 1 The following entries are used to draw the crack tip from point 0 0 0 0 0 0 to point 0 0 0 6 0 0 only DRAW CRACK DIR Y ELSET CZMELE TIPONLY YES 0 0 0 0 0 0 0 0 0 6 0 0 2 The following entries are used to draw the crack and the crack tip The latter is indicated by a line from point 0 0 0 0 0 0 to point 0 0 0 6 0 0 and moved with the crack growth Element set CZMELE is used to draw the actual crack 20 CHAPTER 3 COMMAND DESCRIPTION DRAW CRACK DIR Y ELSET CZMELE COLOR 15 0 0 0 0 0 0 0 0 0 6 0 0 3 1 CONTOUR DRAWING CONTOUR PLOTS 21 3 1 7 DRAW CZM
34. the output files Ui i component of displacement i lt 3 RFi i component of nodal reaction force i lt 3 The following list of element variables are available from the output files Sij ij component of stress i j 3 Eij ij component of strain i j lt 3 PEij ij component of plastic strain i j lt 3 MISES Mises equivalent stress PRESS Hydrostatic presure stress defined as itraco Or i0kk SPi ith principal stress SP1 gt SP2 gt SP3 SDVi ith state variable component PEEQ Equivalent plastic strain The following list of the element variables have been defined by FEPOST H Triaxiality parameter defined as oy o and oy strac o 4 2 Element lists The following list of element types are available from the output files Plane strain elements 58 CHAPTER 4 LIST OF VARIABLES AND ELEMENT TYPES CPE3 CPE4 CPEAR CPE6 CPE8 CPE8R CPE9 CPE9R the last two elements are FECGS elements Plane stress elements CPS3 CPS4 CPSAR CPS6 CPS8 CPS8R CPS9 CPS9R the last two elements are FECGS elements Axisymmetric elements CAX3 CAX4 CAXAR CAX6 CAX8 CAX8R CAX9 CAXOR the last two elements are FECGS elements 3D solid elements C3D4 C3D6 C3D8 C3D8R C3D12 C3D15 C3D20 C3D20R C3D27 C3D27R Chapter 5 QUANTITY DEFINITIONS 5 1 The 7 stress The definition of the T stress can be written spec T oj fos 5 1 where of is the x direction normal stress in
35. to be drawn the different element sets are separated by comma or blanks The following option and data lines are need if one wants to draw the different element sets in different colors COLOR TABLE Format Entry The following data line is need if COLOR TABLE option is required n 1 I n color 1 color 2 color n Examples 1 Use the following entry to draw the FE mesh ofthe whole model 54 CHAPTER 3 COMMAND DESCRIPTION PLOT MESH OUTPUT MPL 2 Use the following entries to draw the FE mesh from the element sets E0000001 E0000002 E0000003 PLOT MESH OUTPUT MPL ELSET E0000001 E0000002 E0000003 COLOR TABLE 3 3 8 16 3 12 Q STRESS EVALUATING THE Q STRESS FOR A GIVEN CURVE 55 3 12 Q STRESS Evaluating the Q stress for a given curve Q STRESS command is used for evaluating the Q stress distribution along a given line or curve This option is currently not yet available Section 5 2 gives the details of the formulation for calculating the Q stress 56 CHAPTER 3 COMMAND DESCRIPTION 3 13 W STRESS Calculating the volume integration W STRESS command is used to calculate the volume integration for the cleavage failure proba bility using weakest link statistics and three parameters Weibull distribution model This option is currently not yet available Chapter 4 LIST OF VARIABLES AND ELEMENT TYPES 4 1 Variable identifiers The following list of nodal variables are available from
36. will interpolate the element variables from the gauss points to the element nodes Thus the element varibles from an analysis run by ABAQUS should be recorded in the gauss integration points Major capabilities of FEPOST include e Tabulating results Tabulating a list of quantities e g displacements at given coordinates summing the nodal reaction force up for a given array of nodes averaging stresses and strains over a material volume etc Displacement along a given curve referring to displacement profile Distribution of solution variables along a given curve for examples the stresses dis tribution Q stress at a given point or along a curve a special option for the purpose of fracture mechancs CHAPTER 1 GENERAL FEATURES calculating the volume integration for the cleavage failure probability a special option for the purpose of fracture mechanics Quantifying the elastic T stress a special option for the purpose of fracture mechan ics e Generating graphic plots Plotting finite element meshes Creating the contour plots Creating the deformed mesh plots Generating the plots of plastic zone 1 2 COMMAND ENTRY 5 1 2 Command entry Uninteractive execution of FEPOST involves entry of alphanumerica commands All entries should be provided in an input file The prompt indicates a command line to be executed with any parameters and required values All
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