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1. jon ee LSS BESS E 5 AESA Se SS A aaa h peas Be NNN vas eS Pe Ie NR ae aw Sai SASS SO eae Ze NEES 2 PSS EES SOS CAE a BTS See Wiss SSR V9 eS AN ARN WAN lt a Eas Figure 8 Mesh with a concentration of elements on a surface 6 2 5 Assignment following chordal error criterion In this section an automatic size assignment is set taking into account a given maximum allowed chordal error 1 Select Mesh gt Unstructured gt Sizes by chordal error 2 The following window appears Figure 9 Assign sizes by chordal error window Assignment following chordal error criterion 91 3 Enter 0 05 as chordal error This error is the maximum distance between the element generated and the real object geometry 4 Enter 4 as maximum meshing size 5 Enter 0 1 as minimum meshing size 6 If the right bottom button is clicked some extra information appears We can select a curved line and see how the mesh will look like in this line Click on the line icon and select line 34 and try to change the chordal error value Leave it at 0 05 7 Press OK 8 To see the sizes that GiD has assigned automatically you can select the Draw gt Sizes gt Surfaces option in the Mesh menu 9 Generate the mesh with the
2. Center 14 7 16 962 36 81 Is trimmed 1 Use Tab and Shift Tab 2 6 3 Signal In complex geometrical models sometimes it is hard to localize an specific entity Using the Signal option in the Utilities menu user can know graphically where the entity is as GiD shows with a red lines cross its potition As an example we will signal the line number 290 1 Selec Utilities gt Signal gt Lines 2 Write in the Command bar the number 290 and click ENTER The result is shown in the next figure Signal 18 The red lines are centered always onto the specific entity independently on the rotations or view movements 2 7 Geometry and Mesh modes In the preprocessing part of GiD there are two basic modes the user can work with geometry and mesh Just in order to see how the mode can be changed we are going to generate a mesh with all the default parameters 1 Select Mesh gt Generate mesh The following Enter size of elernents to be generated 1 window should appear L Get meshing parameters from model 2 Click OK and wait for the mesh generation Once the mesh is generated a window pops up and show the user the result from the mesh generation 3 Click on View mesh option and the following visualization of the model should appear Geometry and Mesh modes 19 Now we are in mesh mode Changing the render mode user can see that the color of the mesh entities also follows the
3. yi Ga Ad A va Nh 2 Select View gt Render gt Flat 3 Select View gt Render gt Smooth Flat render mode draws each geometrical entity using the colour of the layer it belongs to and Smooth mode uses also this criterion but lines are not drawn to represent the geometry in a smoother way The following figure shows the visualization of the model using Smooth render mode Render modes 9 2 4 Change views of the model In the View menu user can find the options to change the point of view in which the model is shown Many of these options are also accessible by the right mouse button menu or the icons toolbar 2 4 1 Zoom To zoom in or out the model user can choose the corresponding options in the Zoom section of the View menu or the right mouse button menu A user friendly way of zooming the model is to use the wheel of the mouse or clicking the center button of the mouse while the Shift key is pressed To get a view which includes the whole model the Frame option must be selected The icons corresponding the zoom operations are the following ones Zoom in sm Zoom out d5 Zoom frame 2 4 2 Pan To move the view of the model user must select the option Pan This option is accessible from the View menu the right mouse button menu or moving the mouse while the Pan 10 Shift key and the right mouse button are pressed The corresponding icon for the pan option is the following one 7 2 4 3
4. Generating semi structured meshes volumes 108 Figure 11 Semi structured volume mesh of tetrahedra As can be seen volume 3 has been meshed with tetrahedra Semi structured volumes are meshed with prisms by default However in this case it was not possible because of volume 2 which has tetrahedra assigned and shares one surface with volume 3 In the following steps a hexahedron mesh is produced 8 Select Mesh gt Element type gt Hexahedra 9 Select volumes 2 and 3 and press ESC 10 Select Mesh gt Generate mesh 11 A window opens asking whether the previous mesh should be eliminated Click Yes 12 Another window appears in which to enter the maximum element size Leave the default value unaltered and click OK The result is the mesh shown in Figure 12 Generating semi structured meshes volumes 109 Figure 12 Semi structured volume mesh of hexahedra In case of volume number 3 there is only one direction in which it can possibly be structured i e in the direction of the prism If the volume is prismatic in more than one direction there are two ways to choose between them selecting one top surface Mesh gt SemiStructured gt Set gt Master surface or the direction of the structure Mesh gt SemiStructured gt Set gt Structured direction The following example explains this procedure 13 Select the option Mesh gt SemiStructured gt Volumes 14 A window opens in which to enter the number of divi
5. It is also possible to assign sizes to geometrical entities so that mesh elements can be concentrated in certain zones In the following steps some examples are given 7 Select Mesh gt Unstructured gt Assign sizes on points 8 A window appears in which to enter the size to be assigned to points Enter 0 1 and click Assign 9 Select point number 15 and press ESC 10 Another window appears in which to enter the size to be assigned to points In this case we donot want to assign sizes to any other points so click Close 11 Select Mesh gt Unstructured gt Assign sizes on lines 12 A window appears in which to enter the size to be assigned to lines Enter 0 5 and click Assign 13 Select line number 25 and press ESC 14 Another window appears in which to enter the size to be assigned to lines In this case we do not want to assign sizes to any more lines so click Close 15 Select Mesh gt Generate mesh Concentrating elements and assigning sizes 111 16 A window appears asking whether the previous mesh should be eliminated Click Yes 17 Another window appears in which the maximum element size should be entered Leave the default value unaltered and click OK The result is not the desired we just get the previous mesh This is because surrounding surfaces and lines are structured so they do not have enough freedom to achive the given sizes 18 Select Mesh gt Unstructured gt Assign entities gt Surfaces 1
6. ne si EVA Ya HA7 NETA S EPRI FAR oS aX BEAN SEO O TANS PATA BEEK QA 7 va Ran gt BRE 4 LRI ne RNA SS BESS SO A AA ani RK p ZANAN NS i E nas ee A AR os RASS z gt DG VS Vy POET VAS 3 KNAV a Rasa Va KD WA KS NA ISAR SS aS KN RAD Ary Bee lt I HigherEntities 2 Interior 1 Boundary Higher entities of the result model 157 A conformal mesh has been achieved all edges are interior higer entitie 2 except the ones on the boundary with higer entitie 1 9 3 3 Creating a non conformal mesh Lg NOTE Non conformal meshes may be used with some calculating modules i e stamping a plate Using non conformal meshes significantly reduces the number of elements in the mesh This cuts down on computation time 1 Select View gt Mode gt Geometry 2 Select Geometry gt Edit gt Uncollapse gt Surfaces Select all the surfaces in the model Press ESC A sufficient number of lines is created so that no surface of the object shares lines with any contiguous surface 3a Select Mesh gt Generate Mesh When the mesh has been generated a window appears with information about the mesh Figure 29 The result is a non conformal mesh composed of far fewer elements than the meshes generated in the previous section about 4000 elements instead of the 10 000 needed to generate the conformal mesh Creating a non c
7. Create contacts Maintain layers Multiple copie Figure 7 The copy window 2 Repeat the rotating and copying process from section for the two auxiliary lines Select the option Lines from the Entities type menu and enter an angle of 36 degrees 3 Select the lines to copy and rotate Do this by clicking Select in the Copy window 4 Press ESC to indicate that the process of selecting lines is finished thus executing the task Rotating and copying the auxiliary lines 50 Figure 8 Result of copying and rotating the line 5 Rotate the line segment that goes from the origin to point 40 0 by 33 degrees and copy it lin Figure 9 Result of the copy by rotation Rotating and copying the auxiliary lines 51 wI NOTE In the Copy window the button may be used to select existing points with the mouse or alternativelly enter its number in the entry field 4 2 7 Intersecting lines 1 Choose the option Geometry gt Edit gt Intersection gt Lines 2 Select the upper circle 3 Select the line resulting from the 33 degree rotation see next figure Figure 10 The two lines selected 4 Press ESC to conclude the intersection of lines 5 A confirmation window appears click Ok 6 Press ESC to finish the intersection function 7 Create a line Geometry gt Create gt Straight line between the existent point 55 0 and the point generated by the intersection 8 Choose the option Geometry gt Edi
8. In order to work with graphs we will use the graphs window The Point evolution graph displays a graph of the evolution of the selected result along all the steps of the default analysis for the selected nodes 1 Select View results gt Graphs gt Point evolution gt Velocity m s gt V 2 Write 20 0 4 in the command line in order to specify the point 3 Affter pressing the Escape key or the middle mouse button the graph will be shown in a separate window Graphs 134 Velocity m s evolution at 20 0 4 The graph is created in the graphset 1 We will create another graph in the same graph Set The Line graph displays a graph defined by the line conectig two selected nodes of Surfaces or volumes or any arbitrary points on any projectable surface and in any position 4 Switch all surface meshes off and let only the three volume meshes on V volumes V cil V wake 5 Select View results gt Graphs gt Line graph gt Velocity m s gt V 6 Write 3 0 4 in the command line in order to specify the initial point 7 Write 50 O 4 in the command line in order to specify the final point Now both graphs are showed in the same graph set Graphs 135 Velocity m s evolution at 20 0 4 Line Graph in wake 6 Step 103 We will rename the graph set 8 In the top part of the window click thel Llicon 9 A window will appear asking for a new name En
9. GiD The universal adaptative and user friendly pre and postprocessing system for computer analysis in science and engineering User Manual Table of Contents Chapters 1 INTRODUCTION 1 1 Models used in this manual 2 INITIATION TO GiD 2 1 User interface 2 1 1 Change theme 2 1 2 Warnline 2 1 3 Command line 2 1 4 Status bar 2 1 5 Contextual menu 2 1 6 Escape function 2 2 Load a model 2 3 Render modes 2 4 Change views of the model 2 4 1 Zoom 2 4 2 Pan 2 4 3 Rotate 2 4 3 1 Set center of rotation 2 5 Layers and groups 2 5 1 Create a layer 2 5 2 Rename a layer 2 5 3 Change the color of a layer 2 5 4 Send entities to a layer 2 5 5 Switch On Off 2 5 6 Freeze a layer 2 5 7 Transparency 2 6 Entities information 2 6 1 Labels 2 6 2 List entities 2 6 3 Signal 2 7 Geometry and Mesh modes 2 8 Pre and Post Pag O Oo OO N A OA Ha A HR HR U U U fF FF e e e e e e e e e Cs E e eE Be he e WO O N OA wo wo A BR BR N Nre e O O O Table of Contents 2 9 Select and display style 3 INITIATION TO PREPROCESSING 3 1 First steps 3 2 Creation and meshing of a line 3 3 Creation and meshing of a surface 3 4 Creation and meshing of a volume 4 IMPLEMENTING A MECHANICAL PART 4 1 Working by layers 4 1 1 Defining the layers 4 1 2 Creating two new layers 4 2 Creating a profile 4 2 1 Creating a size 55 auxiliary line 4 2 2 Dividing the auxiliary line near coordinates 40 0 4 2 3 Creating a 3 8 radius circle around point 40
10. Switch on all the sets again through the View style window by selecting all sets and clicking on the licon 8 3 4 Contour fill cuts and limits Contour fill Pressure Pa 0 55696 0 40175 0 24655 0 091344 0 063861 0 21907 0 3 74AT 0 527 0 66468 0 83988 Menu View results gt Contour Fill 1 Please select View results gt Contour Fill gt Pressure Pa through the menu bar or clicking on or using the Window gt View results window 2 If not all sets show the contour fill like the picture above remember to select BodyBoundary mesh style for all the sets This option allows the visualization of coloured zones in which a scalar variable or a component of a vector varies between two defined values GiD can use as many colours as permitted by the graphical capabilities of the computer The number of colours can be set through Options gt Contour gt Number of colours A menu of the variables to be represented will be shown and the one that is chosen will be displayed using the default analysis and step selected In the model the pressure has been calculated We can visualize the result for each step in a contour fill You can choose the step that you want to view through the View results window or Itt clicking on EE 3 Select the step 103 Several configuration options can be set via the Options menu Contour fill cuts and limits 124 Menu Options gt Contour You can change the color scale in or
11. char filename 1024 fileerr 1024 saul 1024 FILE ip reri int aux J error 0 void jumpline FILE strcpy filename projname strcat filename dat fo fopen filename r for i 0 i lt 6 i jumpline fp fscanf fp sd sd amp Nelem amp Nnod x double malloc Nnod 1 sizeof double y double malloc Nnod 1 sizeof double N int malloc Nelem 1 3 sizeof int if imat int malloc Nelem tl1 sizeof int if N NULL sau2 1024 x NULL y NULL N NULL error l1 error l1 error 1 error 1 184 The main program 185 IL error 4 strcpy fileerr projname strcat fileerr err ferr fopen fileerr w forinti ferr ERROR Not enough memory FAE 7 fprintf ferr Try to calculate with less elements fclose ferr exit l1 for i 0 i lt 6 i jumpline fp reading the coordinates for inod 1 inod lt Nnod inod fscant ip sd lt li lt li aux amp x inod e amp ylinod for 1 0 i lt 6 i jumpline fp reading connectivities for 1elem 1 ielem lt Nelem ielem Escanr ip sd Saux Lor O lt 37 J fscanf fp sd Ni 2elem 1 34 1 fscanf fp Sd amp imat ielem if imat ielem 0 strepy fileerr projname strcat fileerr err ferr fopen fileerr w tprintf ferr ERROR Elements with no mMareria
12. 0 4 2 4 Rotating the circle 3 degrees around a point 4 2 5 Rotating the circle 36 degrees around a point and copying it 4 2 6 Rotating and copying the auxiliary lines 4 2 7 Intersecting lines 4 2 8 Creating an arc tangential to two lines 4 2 9 Translating the definitive lines to the profile layer 4 2 10 Deleting the aux layer 4 2 11 Rotating and obtaining the final profile 4 2 12 Creating a surface 4 3 Creating a hole in the mechanical part 4 3 1 Creating a hole in the surface of the mechanical part 4 4 Creating volumes from surfaces 4 4 1 Creating the prism layer and translating the octagon to this layer 4 4 2 Creating the volume of the prism 4 4 3 Creating the volume of the wheel 4 5 Generating the mesh 4 5 1 Generating a coarse mesh 4 5 2 Generating the mesh with assignment of size around points 4 5 3 Generating the mesh with assignment of size around lines 5 IMPLEMENTING A COOLING PIPE 19 23 23 24 28 37 43 43 43 44 44 44 45 46 46 47 48 51 53 53 54 54 55 56 57 58 58 59 60 61 61 64 66 69 Table of Contents 5 1 Working by layers 5 2 Creating a component part 5 2 1 Creating the profile 5 2 2 Creating the surfaces by revolution 5 2 3 Creating the union of the main pipes 5 2 4 Copying the main pipe 5 2 5 Creating the end of the pipe 5 3 Creating the T junction 5 3 1 Creating one of the pipe sections 5 3 2 Creating the other pipe section 5 3 3 Creating the lines of intersection 5 3 4 D
13. Ctrl d oon Shapefile AYZ points KML NASTRAN mesh STL mesh VRML mesh 3DStudio mesh CONS mesh GID mesh Surface mesh Ply mesh OBJ Wavefront mesh VTE Vowels XYZ nodes UNV STAR CD GDAL EMA3D Amelet Batch file Insert GID model Ctri b 142 Sometimes the original file has incompatibilities with the format required by GiD These incompatibilities must be overcome manually This example deals with various solutions to the difficulties that may arise during the importing process 9 1 1 Importing an IGES file 1 Select Files gt Import gt IGES 2 Select the IGES formatted file base igs and click Open Importing an IGES file 143 Gi Processing IGES Percentage E Inside Stop Reading the file Gd Repairing Model Percentage Done C ll s istststssSSC C E Inside Repairing the model IGES Global section parameters Sending System GID File name C gid project tutoriales Importing_Iutorial base_tmp igs System ID GID Preprocessor Version 9 2 9b Model Scale 1 Unit flag Millimeters Date And Time Exchange 19 3 2010 13 28 22 Minimum Resolution Le 008 Approximate Maximum Coordinate 454 004 Organization CIMNE International Center for Numerical Methods in Engineering Specification Version 3 2 Collapse geometry Time 1 seconds Created
14. Layer11 set as transparent Transparency 15 2 6 Entities information 2 6 1 Labels Using the option Labels present in the View menu and also in the right mouse button menu user can see the number of the entities of the model Either for points lines Surfaces or volumes user can choose between viewing the numbers of all the entities or just the selected ones In the following figure the model can be seen with the number of some entities Labels 16 As it can be seen the colors of the numbers of the entities follows the philosophy of the colors of the entities in GiD volume numbers are in light blue surface numbers are in pink and so on In order to get a better visualization set the render mode to normal when showing labels 2 6 2 List entities User have also the option of viewing all the characteristics of a specific entity by selecting List in the Utilities menu or clicking in the icons toolbar For example 1 Select Utilities gt List gt Surfaces in the top menu 2 Select some surfaces of the model 3 Press Escape An example of the information got using this option is the following figure List entities 17 List Entities NURBSURFACE Num 11 Layer Layer HigherEnt 1 Conc 0 Groups 0 No meshing information Lines Points Knots inU Knots in V Num Lines 5 Line Orientation Fi DIFF1ST DIFFLST DIFFLST DIFF1ST DIFFLST Normal 1 1 4853e 008 1 0605e 008
15. Sar te a cs Ek ai Ai ais tity i 1 PEI r a T iE Fy mE eal ts Ov BEETS NAN eile F y a ae aa The mesh generated above is composed of tetrahedral elements of four nodes but GiD also permits the use of hexahedral eight nodded structured elements We will generate a structured mesh of the volume of the cube This is done by selecting Mesh gt Structured gt Volumes gt Assign number of cells Now select the volume to mesh and press ESC Then a window appears where the number of subdivisions for the volume limit lines should be entered Enter 10 and click Assign and select one of the lines in X axis the parallel lines are also selected Press ESC The same window appears again click Assign and select one of the lines in Y axis the parallel ones are also selected Press ESC Again click Assign and select one of the lines in Z axis the parallel ones are also selected Press ESC Click Close when the window appears again Then create again the mesh Creation and meshing of a volume 42 Enter value window eal Progress in meshing B Mesh generated Num of Tetrahedra elements 6000 WU Num of nodes 1331 2 Enter number of cells to assign to lt lines Num nodes Meshing evolution Memory KB 4 5 6 Time seconds w NOTE GiD only allows the generation of structured meshes of 6 sided volumes Wi
16. Select Mesh gt Element type gt Quadrilateral Select surfaces number 24 and 12 and press ESC 2 Select Mesh gt Generate mesh 3 A window comes up asking whether the previous mesh should be eliminated Click Yes 4 Another window appears in which the maximum element size can be entered Leave the default value unaltered and click OK The result will be the mesh illustrated in Figure 6 Generating the mesh using quadrilaterals 103 a DEN TEN cf za peal LE eee A ar lt g s P a a Ba 7 a n z Ne gt a z Eg a amp n a a m E E lt E a ti a ie enh Figure 6 An unstructured mesh generated using quadrilaterals 5 The surface is meshed with quadrilaterals forming an unstructured mesh surface 12 seems structured but if you zoom in you will see that it is not 7 2 5 Generating a structured mesh surfaces 1 To mesh surfaces with a structured mesh select the option Mesh gt Structured gt Surfaces gt Assign number of cells 2 Select all top surfaces 9 24 26 and 12 and press ESC 3 A window appears in which to enter the number of divisions that the lines to be selected will have Enter 4 4 Click Assign and select one vertical line parallel to the Y axis Press ESC 5 Another window appears in which to enter the number of divisions on the lines Enter 6 6 Click Assign and select the 4 bottom lin
17. Select the file where the second part created in section Creating the T junction pag 75 was saved Click Open 3 The T junction appears Bear in mind that the lines which define the end of the first pipe background of the T junction and which have been imported were already present in the first file Notice that the lines are duplicated This overlapping will be remedied by collapsing the lines 4 Check duplicated lines with the tool View gt Higherentities gt Lines Importing a GiD file 79 Higherentities 2 Interior deidan Pa 1 Boundary NINA Figure 17 Importing the T junction file to the main file Some entities are duplicated and must be collapsed 5 Choose the option Geometry gt Edit gt Collapse gt Lines Select the overlapping lines and press ESC 5 4 2 Creating the final volume Now we have a volume of the T junction and we want to create another volume with the rest of the piece connected to the first volume Two volumes are connect if they share some surface we will reuse the ring surface of the first volume for the new volume 1 Set off the layers parti and union 2 Send the shared surface to the parti layer to facilitate the selection of the new volume boundary select parti use Send to gt Surfaces and select the surface of the image and press Escape Figure 18 Surface to be shared 3 Set off the layers pipel and pipe2 and set on parti and union and send p
18. and then s With the succession option you specify an axis that will be used to create cut planes orthogonal to this axis The number of planes is also asked for 3 Draw a line through the X axis in the middle of the model and ask for 7 cuts You should obtain 7 parallel planes to Y axis Note after clicking the first point pressing the Alt key while moving the mouse the dynamic line will be axis aligned or at 45 degrees 4 Now change the display style Utillities gt View style in order to see only the cuts You can see that several layers have appeared a prefix like CCutSetX indicating which mesh or set has been cut These names can always be changed through the Window gt View Style Select all the layers except the cuts and change their style to Boundaries You can rotate the model in order to see the contour fill result on the cut planes 5 In the same window select all the CCutSetX and click on Delete button in order to delete all the cuts 6 Select BodyBoundary as mesh style to visualize the contour fill of pressure again 7 Select Options gt Contour gt Reset all in order to set all the defaults options Contour fill cuts and limits 126 Define limits You can set the limit values for the contour fill In our case we only want to see the positive values In order to do this we will set the minimum value to O 7 1 Select Options gt Contour gt Define Limits through the menu bar or clicking on i C
19. this case 0 0 0 and 0 0 10 Option Do extrude surfaces must be selected this option allows us to create the lateral surfaces of the cube Fill in the rest of variables as shown in the following image Creation and meshing of a volume 38 Entities type Surfaces Transformation Translation First point Num x 0 0 y 0 0 Be Second point Numi x 0 0 y 0 0 al Collapse Do extrude Surfaces E Create contacts C Maintain layers Multiple copies 1 Ig NOTE In the Copy and Move windows the button may be used to select existing points with the mouse or alternativelly enter its number in the entry field La NOTE If we look at the Copy Window we can see an option called Collapse By activating this option point 6 will be merged with point 5 when the entities are copied By labeling the entities we could verify that only one point has been created If the user does not choose option Collapse when the entities are copied in this case from point 1 to point 5 GiD would create a new point point 6 with the same coordinates as point 5 To finish the copy command click Select select the surface and then press ESC We obtain the following surfaces Creation and meshing of a volume 39 Now we can generate the volume delimited by these surfaces To create the volume simply select the command Geometry gt Create gt Volume gt By co
20. 1 sizeof double if y NULL error 1 N int malloc Nelem 1 3 sizeof int 1f N NULL error 1 imat int malloc Nelem l1 sizeof int if N NULL error 1 if error strcpy fileerr projname strcat fileerr err ferr fopen fileerr w fprintf ferr ERROR Not enough Memory s fprintf ferr Try to calculate with less elements fclose ferr exit 1 The main program 180 for 1 07 1 lt 6 i Jumoline fp Space is reserved for storing the coordinates of the nodes pointers x y the connectivities pointer N and the materials corresponding to each element pointer imat In case of error insufficient memory a file is created with the extension err This file contains information about the error and the program is aborted The next six lines are jumped over reading the coordinates for inod 1 inod lt Nnod incat PSCant ip sd gli lf Laux amp x inod yy inod for i 0 i lt 6 i jumpline fp The coordinates of the nodes are read and stored in the x and y variables The node identifier indexes the tables of coordinates reading connectivities for 1elem 1 ielem lt Nelem ielem fscanr fp sd Saux for O j lt 37 Ft fscanf fp sd amp N relem 1 3 fscanf fp Sd amp imat ielem if imat ielem 0 strepy fileerr projname strcat fileerr err ferr fopen fil
21. 9 2 Correcting errors in the imported geometry The great diversity of versions formats and programs frequently results in differences errors between the original and the imported geometry With GiD these differences might give rise to imperfect meshes or prevent meshing altogether In this section we will see how to detect errors in the imported geometry and how to correct them Importing the same file with different versions of GiD might produce slight variations in the results For this reason from now we will use a project that contains the original IGES file translated into GiD format 1 Select Files gt Open 2 If a dialog window appear asking to save changes to the project click No 9 2 1 Meshing by default 1 Select Mesh gt Generate Mesh Meshing by default 145 A window comes up in which to enter the maximum element size for the mesh to be generated Leave the default value provided by GiD unaltered and click OK When the GiD finishes the meshing process an error message appears This error is due to a defect in the imported geometry As the window shows there have been errors meshing surface number 124 Mesh errors Surfaces 1 wrong surfaces Num Description J24 Couldn t mesh at this location Dialog warning window of meshing errors In this part of the tutorial we focuson repairing surface number 124 To locate surface 124 select the line 124 Couldn t mesh at this location in the dialog bo
22. From step 3 to step 8 Duration Set duration by Total Time 5 5 Static analysis animation profile use step values as scaled delays Delay between steps 800 ms O Use step values as seconds Play Step number 1 Step value 91 5 1 isl Save image E Save PNG on p Save animation E Save AVI MS Video 1 on f Lreate a stereoscopic animation If one result has several steps you can visualize them in an animation In this case we will Animate 121 use the iso surfaces result 1 Select View gt Render gt Smooth 2 Select Window gt Animate to open the animation window Please notice that we have from step 1 to 13 We will do the animation only of some of these steps 3 Check the From step option and set 3 to step 8 4 Select the Delay between steps option and set it to 800 ms The animation should take 4 seconds 5 Try it clicking on the play icon We will record a video during the animation 6 Once the animation is finished check the Save option on the Save animation part You can choose from several video formats 7 Select AVI mjpeg to include this animation in a MS PowertPoint an apropiate codec is needed like the one supplied with Combined Community Codec Pack CCCP 8 Select a folder where the video will be saved clicking on the folder icon or writing the path in the text entry 9 Click on the play button and the recording will begin This step could take a little bi
23. In this tutorial you will become familiarized with the mesh generating combinations available in GiD 2 A structured mesh is one in which each node is connected to a constant number of elements 3 A semi structured volume mesh is one in which you can distinguish a fixed structure in one direction i e there is a fixed number of divisions However within each division the mesh need not be structured This kind of mesh is only practical for topologically prismatic volumes Generating the mesh by default 99 7 2 1 Generating the mesh by default In order to get the same results we will reset the mesh options 1 Open the preferences window selecting Utilities gt Preferences 2 Select the Meshing card click on Reset and then Accept 3 Select Mesh gt Generate mesh 4 A window comes up in which to enter the maximum element size for the mesh to be generated As default value could change from one version of GiD to another insert 2 to get the same results as shown in images OK 5 A meshing process window comes up Then another window appears with information about the mesh generated Click View mesh to visualize the mesh 6 The result is the mesh in Figure 2 There are various surfaces and volumes By default mesh generation in GiD obtains unstructured meshes of triangles on surfaces and tetrahedra on volumes 7 Select Render gt Flat in mouse menuto see the mesh in render mode As is shown in Figure 3 volume meshes are repre
24. Layer colors Selecting View gt Mode gt Geometry user can change to the geometry mode again The lt Jicon in the toolbar switch between both modes GiD basically works in two modes preprocessing and postprocessing To change between both modes please select Files gt Postprocess or Files gt Preprocess or clicking in the upper toolbar We will use a different model to work in postprocess mode 1 Open the box3D gid project 2 Select Files gt Postprocess Through the Select amp Display Style window several options can be specified for volumes surfaces and cuts Among these options volumes surfaces and cuts can be switched on and off their colour properties can be changed and their transparency too Other interesting options which can be changed are the style of the set and the width of the elements edges From this window volumes surfaces or cuts can be deleted or their names can be Select and display style 20 modified 1 Select Window gt View style using the menu bar or clicking on Our model only has 1 layer We will create a new layer with some elements 2 Press button Send to gt New set long name 3 Select some elements me 4 Press Escape 5 A window appears asking for a name Enter Aux 6 Press Accept A new layer is created with the selected elements Now we will change the color of the new layer 7 Click on the colored square next to the layer name A new wi
25. assign the weight correctly We want to concentrate the elements in the left zone of the square Select both horizontal lines and press ESC A window appears to enter the weights values Both lines should have the same direction so enter a weight of 0 5 to the beginning of the line and click Ok Press ESC again to leave the function AAAAANAAYS AAAAAAAAAA i NAANAAAAAA HESSEN HS PESSE Creation and meshing of a volume 37 3 4 Creation and meshing of a volume We will now present a study of entities of volume To illustrate this a cube and a volume mesh will be generated Without leaving the project save the work done up to now by choosing Files gt Save and return to the geometry last created by choosing Geometry gt View geometry In order to create a volume from the existing geometry firstly we must create a point that will define the height of the cube This will be point 5 with coordinates 0 0 10 Superimposed on point 1 To view the new point we must rotate the figure by selecting from the Mouse Menu Rotate gt Trackball This option is also available in the toolbar Rotate the figure until the following position is achieved and press ESC 2 Next we will create the upper face of the cube by copying from point 1 to point 5 the surface created previously To do this select the copy command Utilities gt Copy In the Copy window we define the translation vector with the first and second points in
26. between points 1 and 3 3 0 10 0 1 0 0 0 2 10 0 0 We will now generate the second line We will now use again the Coordinates Window to enter the points Utilities gt Tools gt Coordinates Window Select the line creation tool in the toolbar a Enter point 0 10 0 in the Coordinates Window and click Apply Coordinates window C System Cartesian Local axes Global x 0 00000 y 10 0000 z 0 00000 Create new point Ask With option Contextual gt Join Ctrl a mouse menu click over point 1 A line should be created between 0 10 0 and 0 0 0 Press Escape twice With this a right angle of the square has been defined Center the image in the screen with View gt Zoom gt Frame Finish the square by creating point 10 10 0 and the lines that join this point with points 2 and 3 Creation and meshing of a surface 29 3 0 10 0 1 0 0 2 10 0 0 Now we will create the surface that these four lines define To do this access the create Surface command by choosing Geometry gt Create gt NURBS surface gt By contour This option is also available in the toolbar _ lt I GiD then asks the user to define the 4 lines that describe the contour of the surface Select the lines using the cursor on the screen either by choosing them one by one or selecting them all with a window Next press Escape twice As can be seen below the new surface is created and appears as a smaller magenta colo
27. clicking on throught the icon bar This icon can also be found in the Page and capture settings window In this case the image format is choosen while saving the file in the Files of type combobox CAD CLEANING OPERATIONS 140 141 9 CAD CLEANING OPERATIONS IMPORTING FILES The objective of this case study is to see how GiD imports files created with other programs The imported geometry may contain imperfections that must be corrected before generating the mesh For this study an IGES formatted geometry representing a stamping die is imported These steps are followed Importing an IGES formatted file to GiD Correcting errors in the imported geometry and generating the mesh Generating a conformal mesh and a non conformal mesh Pice provided by courtesy of PSA DEGAD MAC AIE 9 1 Importing on GiD GiD is designed to import a variety of file formats Among them are standard formats such as IGES DXF or VDA which are generated by most CAD programs GiD can also import meshes generated by other programs e g in NASTRAN or STL formats Importing on GiD Es New Open Recent projects is Save Gh Save as Export lt 2 Postprocess Recent post files 9 Print to file Print The file importing process is not always error free Utilities Data Page and capture settings Mesh Calculate Help lt D rs Layer STEP DXF Parasolid ACK
28. enter the element size around the point to be selected Enter 0 7 and click Assign 3 Select only the points on the wheel profile see next figure One way of doing this is to select the entire part and then deselect the points that form the prism hole Press ESC to conclude the selection process 4 The window appears again click Close to finish Figure 34 The selected points of the wheel profile 5 Choose Mesh gt Generate mesh 6 A window opens asking if the previous mesh should be eliminated Click Yes Another window appears in which the desired element size should be entered Leave the previous value of 10 unaltered Erase old mesh Cancel Figure 35 Erasing old mesh 7 A third window shows the meshing process Once it has finished click OK to visualize the resulting mesh Generating the mesh with assignment of size around points 66 Figure 36 Mesh with assignment of sizes around the points on the wheel profile 8 A greater concentration of elements has been achieved around the points selected 9 Choose View gt Mode gt Geometry to return to this visualization 4 5 3 Generating the mesh with assignment of size around lines 1 Open the Preferences window which is found in Utilities and select the Meshing gt Main branch In this window there is an option called Unstructured size transitions which defines the size gradient of the elements A high transition number means a fast grown of sma
29. gives the total number of materials in the project nmats returns the total number of materials Mat Density loop materials format S41 13 5e set var PROP1 real Operation MatProp Density real MatNum PROPI end This provides a rundown of all the materials in the project and a list of the identifiers and densities for each one MatProp density real returns the value of the property density of the material in a real format Operation expression returns the result of an arithmetic expression This operation must be expressed in C Set var PROP1 real Operation MatProp Density real assigns the value returned by MatProp which is the value of the density of the material to the variable PROP1 a real variable PROP1 returns the value of the variable PROP1 MatNum returns the identifier of the present material Creating the Data Format File Template file 169 Point condicions Set Cond Point Weight nodes xset var NFIX int CondNumEntities int Concentrate Weights NFIX This provides the number of entities with a particular condition Set Cond Point Weight nodes this command enables you to select the condition to work with from that moment on For the present example select the condition Point Weight CondNumeEntities int returns the number of entities with a certain condition Set var NFIX int CondNumeEntities int assigns the value returned by the comman
30. is a cooling pipe composed of two sections forming a 60 degree angle The modeling process consists of four steps Modeling the main pipes Modeling the elbow between the two main pipes using a different file Importing the elbow to the main file Generating the mesh for the resulting piece At the end of this case study you should be able to use the CAD tools available in GiD as well as the options for generating meshes and visualizing the result 7 eo 5 1 W orking by layers Working by layers 70 Various auxiliary lines will be needed in order to draw the part Since these auxiliary lines must not appear in the final drawing they will be in a different layer from the one used for the finished model Create the layers called part1 union and delete the layer LayerO Choose part1 as the activated layer to use From now on all the entities created will belong to this layer 5 2 Creating a component part In this section the entire model except the T junction will be created The model to be created is composed of two pipes forming a 60 degree angle To start with the first pipe will be created This pipe will then be rotated to create the second pipe 5 2 1 Creating the profile 1 Choose the Line option located in Geometry gt Create gt Straight line 2 Enter the following new points in the command line 0 11 8 11 8 31 11 31 11 11 and 15 11 Press ESC twice t
31. iy Pope ee ie I ae Yj A ee J F Al iis RO 3 N V7 Nel a ae aie Figure 4 The lines to be selected 72 4 Click Select and select the four lines that define the right end of the pipe see figure above Press ESC when the selection is finished TE AeA Al J 1 ka all N f Sa nih ian ek fi i i t HAL i M UN _ See Figure 5 Result of the extrusion by rotation 5 2 4 Copying the main pipe IMPLEMENTING A COOLING PIPE gt Creating a component part gt Copying the main pipe Align uses a rigid body movement defined by three source points and its destination points 1 From the Copy window select Surfaces and Align Choose the Two Dimensions option The source points S1 S2 and its destination points D1 D2 are highlighted in the image Ensure the Do Extrude menu is set to No and set Maintain layers Copying the main pipe 73 qa NOTE In the Copy window the button a may be used to select existing points with the mouse or alternativelly enter its number in the entry field Figure 6 pairs of points to define the Align movement 2 Click Select and select all the surfaces of the layer part1 and press ESC when the selection is finished Figure 7 Geometry of the two pipes and its union 5 2 5 Creating the end of the pipe Creating the end of the pipe 74 1 From the Copy window s
32. key or click Finish in the Copy window in order to conclude the operation The result is shown in next figure Figure 15 The part resulting from this process 4 2 12 Creating a surface 1 Create a NURBS surface To do this select the option Geometry gt Create gt NURBS surface gt By contour This option can also be found in the GiD Toolbar 2 Select the lines that define the profile of the mechanical part and press ESC to create the surface 3 Press ESC again to exit the function Creating a surface 56 Figure 16 Creating a surface by contour gg NOTE To create a surface there must be a set of lines that define a closed contour 4 3 Creating a hole in the mechanical part In the previous sections we drew the profile of the part and we created the surface In this section we will make a hole an octagon with a radius of 10 units in the surface of the part First we will draw the octagon 1 Select from the menu Geometry gt Create gt Object gt Polygon to create a regular polygon 2 Enter 8 as the number of sides of the polygon 3 Enter 0 0 0 as the center of the polygon use Ctrl a keys to swap to select new point mode if required 4 Select Positive Z as the normal of the polygon this mean a normal direction 0 0 1 5 Enter 10 as the radius of the polygon and press ENTER Press ESC to finish the action We get the result as shown in figure 20 As we only need the boundary we should remove the associated su
33. outer Set pipel inner as layer to use with a lt Double click gt Creating one of the pipe sections 76 3 Choose Geometry gt Create gt Point and enter new point 0 9 4 set pipel outer as layer to use and create the new point 0 11 Press ESC to conclude the creation of points 5 From the Copy window select Points and Rotation Enter an angle of 180 degrees and from the Do extrude menu select Lines The axis of rotation is the x axis Enter two points defining the axis one in First Point and the other in Second Point for example 0 0 O and 1 0 0 check Maintain layers and set Multiple copies to 2 6 Click Select and select the two points just created Press ESC Figure 11 the current model 7 Create a surface choose Geometry gt Create gt NURBS Surface gt By contour and select the four lines Press ESC twice 8 From the Copy window choose Surfaces and Translation In First Point and Second Point enter the points defining the translation vector Since the pipe section must measure 40 length units the vector is defined by points 0 0 0 and 40 O 0 9 From the Do extrude menu choose the Volumes option and set Multiple copies to iF 10 Click Select to select the surface Press ESC to conclude the selection process Figure 12 Creating a pipe by extruding the ring 5 3 2 Creating the other pipe section 1 Create a new layer named pipe2 with two child layers inner and oute
34. set via the Options menu Menu Options gt Stream lines The options can be also managed through the Size amp detail window 10 Select Options gt Contour gt Color Scale gt Standard 11 Select Options gt Stream lines gt Size amp detail 12 Check the Dynamic update option 13 Select Stream contour filled The stream lines will be drawn with the colors used in the velocity contour fill 14 In the Arrows options set 30 for the Size option 15 Set 10 for the Spacing option 16 Check the Show Arrows option 17 You may play with the diferent stream types points ribbons or 4 sided prisms If the ribbons type is selected you may adjust the initial swirl to rotate the ribbon 18 Close the window 19 Select Options gt Stream lines gt Delete all lu NOTE A way to achive the best results is to first create a cut of the volume mesh throught the region of interest and then use these nodal information as support to create stream lines and its options along line in a quad etc Stream lines 133 8 3 9 Graphs Menu View results gt Graphs From this menu several graphs types can be created we will try some of them Graphs are Supported for results defined over nodes Graphs are organized into graph sets in order to ease the management Each set shares the same units for each axis When a graph is created is placed in the current graphset if the units are the same otherwise a new graphset is created
35. 10 2 3 Creating the Conditions File Create the cmas2d cnd file which specifies the boundary and or load conditions of the problem type in question In the present case this file is where the concentrated weights on specific points of the geometry are indicated Creating the Conditions File 165 Enter the boundary conditions using the following format CONDITION Name of the condition CONDTYPE Type of entity which the condition is to be applied to This includes the parameters over points over lines over surfaces over volumes or over layers In this example the condition is applied over points CONDMESHTYPE Type of entity of the mesh where the condition is to be applied The possible parameters are over nodes over body elements or over face elements In this example the condition is applied on nodes QUESTION Name of the parameter of the condition VALUE Default value of the parameter END CONDITION In GiD the information in the cmas2d cnd file is managed in the conditions window which is found in Data gt Conditions Point Weight Weight 0 Assign Entities Draw Unassign The GiD Conditions window for assigning the cmas2d boundary and load conditions CONDITION Point Weight CONDTYPE over points CONDMESHTYPE over nodes QUESTION Weight VALUE 0 0 HELP Concentrated mass END CONDITION 10 2 4 Creating the Data Format File Template file Create the cmas2d bas file Th
36. 835 points 581 lines 0 surfaces 0 volumes ImportT olerance 0 0440195 Importing process information After the importing process the IGES file that GiD has imported appears on the screen File base igs imported by GiD Importing an IGES file 144 Mi NOTE One of the operations in the importing process is repairing and collapsing the model We say that two entities collapse when the distance between them being less than the Import Tolerance they become one The Import Tolerance value may be modified by going to the Utilities menu opening Preferences and selecting Import and Export from the tree By default the Automatic import tolerance value is selected With this option selected GiD computes an appropriate value for the Import Tolerance based on the size of the geometry Collapsing the model may also be done manually This option is found in Geometry gt Edit gt Collapse gt Model Preferences Window EF General Import i Interface Automatic collapse after import Other Automatic import tolerance value E Graphical Import tolerance 0 0440195 Appearance Colours Collapse Ignoring layers Each layer separately 7 System IGES Curve on surface from 3D Et Meshing C IGES Create all in layer to use Main Export Pa IGES B Rep output style Boundary Layer Cartesian mesher Sphere mesher Cuba mesher be Fonts Grid i Postprocess Default Values The preferences window
37. 9 Select Surfaces 26 and 12 Press ESC 20 Select Mesh gt Unstructured gt Assign entities gt Lines 21 Select lines 48 26 and 27 Press ESC 22 Select Mesh gt Generate mesh 23 A window appears asking whether the previous mesh should be eliminated Click Yes 24 Another window appears in which the maximum element size should be entered Leave the default value unaltered and click OK The result is the mesh shown in Figure 14 Figure 14 Unstructured size assigned in a point and a line 10 Start Weight and End Weight refer to the start point and end point of the line oriented as it is drawn when you select it 7 2 9 Generating the mesh using quadratic elements Enlarge one area of the mesh with the zoom Generating the mesh using quadratic elements 112 1 Select Label gt All in gt Points The result is shown in Figure 15 754 89 16 50 R76 90 15 52 Figure 15 Each number identifies a node There is a node for each element vertex 2 The node identifiers created by generating the mesh appear on the screen There is one identifier for each vertex of each element 3 Select Mesh gt Quadratic type gt Quadratic 1 NOTE By default GiD meshes with first degree linear elements To find out which mode GiD is working in go to Mesh gt Quadratic type 4 Select Mesh gt Generate mesh 5 A window opens asking whether the previous mesh should be eliminated Click Yes 6 Another wi
38. ESC to indicate that the process of dividing the line is finished Press ESC again to finish the dividing function Figure 3 Division of the straight line near point coordinates 40 0 Creating a 3 8 radius circle around point 40 0 46 4 2 3 Creating a 3 8 radius circle around point 40 0 1 Choose the option Geometry gt Create gt Object gt Circle 2 The center of the circle 40 0 is a point that already exists To select it go to Contextual gt Join Ctrl a in the mouse menu right click The pointer will become a Square which means that you may click an existing point 3 The Enter Normal window appears Set the normal as Positive Z and press OK 4 Enter the radius of the circle The radius is 3 8 Two circumferences are visualized the inner circumference represents the surface of the circle Press ESC to indicate that the process of creating the circle is finished Figure 4 Creating a circle around a point 40 0 In GiD the decimals are entered with a point not a comma 4 2 4 Rotating the circle 3 degrees around a point 1 Use the Move window which is located in Utilities gt Move 2 Within the Move menu and from among the Transformation possibilities select Rotation The type of entity to receive the rotation is a surface so from the Entities type menu choose Surfaces 3 Enter 3 in the Angle box and check the Two dimensions option Provided we define positive 2D rotation in the mathematic
39. Fle t contains the exact coordinates of the center of masses project nametog void output CREATES the res file it contains the distance of each element relative to the center of masses of the object oroject_name post res cmas2d c solver structure gg NOTE The cmas2d c code is explained in the appendix 10 2 6 Creating the Execution File for the Problem Type Create the cmas2d win bat file This file connects the data file s dat to the calculating module the cmas2d exe program When the GiD Calculate option is selected it executes the bat file for the problem type selected When GiD executes the bat file it transfers three parameters in the following way parameter 3 bat parameter 2 parameter 1 parameter 1 project name parameter 2 project directory parameter 3 Problem type location directory Li NOTE The win bat fiile as used in Windows is explained below the shell script for UNIX systems is also included with the documentation of this tutorial Creating the Execution File for the Problem Type 173 rem OutputFile 2 1 log A comment line such as rem OutputFile file name log means that the contents of the file indicated will be shown if the user clicks Output View in Calculate gt Calculate window In this example the log file is shown This file contains the coordinates of the center of mass Project Starttime UID Priority T The process window rem Err
40. IAL Air QUESTION Density VALUE 1 01 HELP material density END MATERIAL MATERIAL Steel QUESTION Density VALUE 7850 HELP material density END MATERIAL MATERIAL Aluminium QUESTION Density VALUE 2650 HELP material density END MATERIAL BEK Density 1 01 Assign Draw Unassign The GiD Materials window for assigning materials Creating the General File 164 10 2 2 Creating the General File Create the cmas2d prb file This file contains general information for the calculating module such as the units system for the problem or the type of resolution algorithm chosen Enter the parameters of the general conditions in cmas2d prb using the following format PROBLEM DATA QUESTION Name of the parameter If the name is followed by the CB instruction the parameter is displayed as a combo box The options in the menu must then be entered between parentheses and separated by commas For example Unit_System CB SI CGS User VALUE The default value of the parameter END GENERAL DATA In GiD the information in the cmas2d prb file is managed in the problem data window which is located in Data gt Problem Data Problem Data Unit System SI Title Default_title The GiD Problem Data window for configuring of the general conditions of the cmas2d module PROBLEM DATA QUESTION Unit System CB SI CGS User VALUE S1 QUESTION Title VALUE Default Cirie END GENERAL DATA
41. NOTE It is important to note that the Contextual submenu in the Mouse Menu will always offer the options of the command that is currently being used In this case the corresponding submenu for line creation has the following options O Cometul Bss Join Ctrl a crom Point In Line Point In Surface x Pan Tangent In Line Redraw Normal In Surface Render Arc Center Label r Line Parameter Layer r Options of Switch full screen Undo Close Wha eee Number sl Quit Escape Ld NOTE With option Join a point already created can be selected on the screen The command No Join is used to create a new point that has the coordinates of the point that is selected on the screen We can see that the cursor changes form for the Join and No Join commands E Cursor during use of Join command T Cursor during use of No Join command Now choose on the screen the first point and then the second which define the line Finally press Escape to indicate that the creation of the line is completed Press Escape again to end the line creation function if you don t press Escape you can continue creating lines Once the geometry has been created we can proceed to the line meshing In this example this operation will be presented in the simplest and most automatic way that GiD permits To do this from the Top Menu select Mesh gt Generate mesh And an Auxiliary Window appears in which the size of the elements should be defined by Creati
42. Num of nodes 6238 Num nodes Meshing evolution Memory KB 10000 Q 0 2 4 6 8 10 12 1416 18 20 Time seconds indow with information about the generated mesh 9 The imported piece is now meshed The mesh of the imported geometry 9 3 The conformal mesh and the non conformal mesh In the previous section after correcting some errors we were able to mesh the imported geometry thus obtaining a non conformal mesh A conformal mesh is one in which the elements share nodes and sides To achieve this condition contiguous surfaces of the piece must share lines and points of the mesh Most calculating modules require conformal meshes however some modules accept non conformal meshes A non conformal mesh normally requires less computation time since it generates fewer elements 9 3 1 Global collapse of the model Global collapse of the model 150 1 After generating the mesh select View gt Higher entities gt Edges ara ERNS DA 7 Z A D a BRA eh RY SI Kir ERNS SERRA RY ER Tatas aN 88 Seas A7 Sr Ud ZVAN ATATA AVAT ESEO na KN NAN ERR HigherEntities BLY ip ay SA 4 Other 3 Other 2 Interior 1 Boundary The higher edges visualization 2 Visualization of higer entities of edges shows that in the interior of the piece some surfaces are isolated 3 Press ESC to finish higer entities visualization 4 To generate a conformal mesh first execute a global collapse of the mod
43. Point Two dimensions must be unchecked Be sure to enter 2 in Multiple copies and select all lines and press ESC when the selection is finished 2 Rotate the view from the mouse menu Rotate gt Trackball and choose Render gt Flat to visualize a more realistic version of the model Figure 3 The pipe with disks created by rotating the profile 3 Return to the normal visualization with Render gt Normal This option is more comfortable to work with To return to the side view elevation choose in the mouse menu Rotate gt Plane XY Original 5 2 3 Creating the union of the main pipes 1 Choose the Zoom gt In option from the mouse menu Magnify the right end of the model and rotate the view to facilitate the selection 2 Set union as current layer to use with a lt Double click gt 3 From the Copy window select Lines and Rotation Enter an angle of 120 degrees and select the rotation center 160 25 as First point Since the rotation may be done in 2D choose the option Two Dimensions From the Do extrude menu select Surfaces and be sure that Multiple copies is land Maintain layers is unset then the new entities will be created in the layer to use instead of the layer of the source curves Creating the union of the main pipes peta es ET en Te PRES EF rana K 1 i r Paane ies ae l SAM T RTF i Poel il F AE RA F ae lt a aE Hoots Teel of Fld
44. Pressure through the menu bar or clicking on the gt In the following questions How many isosurfaces Enter 1 Enter the 1 value Enter 0 Select View Results gt Contour Fill gt Pressure 9 Set the minimum value to 0 10 Select Options gt Contour gt Min options gt Out min color gt Transparent 11 Select Options gt Contour gt Color scale gt Terrain Map 12 Select Options gt Iso surface gt Color mode gt Monochrome 13 Select Options gt Iso surface gt Change color to change the color of the iso CON Or Combined results 128 Surface Note On newer version of GiD step 2 and step 3 is not needed 8 3 6 Stereo mode 3D Stereo E Use stereo stereo mode Anaglyph colors bd eyedistance ES switch eyes eye distance mode scaled with the model left color mask red E green blue alpha right color mask red green blue alpha Shadow C Use shadow black shadow color a ambient 0 020 al shadow bias 0 002 r L finer silhouette FramebufferObject quality medium Mirror E Use floor As mirror edgerelief no backlight mirror colour mirror attached to object mirror angle 0 0 mirror height 0 25 mirror size 2 00 C Dynamic update Menu View gt Advanced viewing settings If you have an anaglyphic glasses you can try this option The model can be set as an anaglyphic image in order to provide a stereoscopic 3D effect when viewed with 2 color glasses
45. Ps AAN KO z A Pick LEFTMOUSE to desplace view ESC to quit ix Pick LEFTMOUSE to desplace view ESC to quit E Command pal Zoom 1x Nodes 0 Elements 0 Render Flat Layers 3 3003 6 406 01 0 Pre 2 1 1 Change theme User can choose between Classic and Dark themes which change drastically the GUI appearance User can also choose between some icon sizes in each theme Change theme 4 These options can be changed in GiD Theme option inside Utilities gt Preferences gt Graphical gt Appearance tab GiD Theme Theme Classic GID Theme Y Theme size Mediurn T 2 1 2 Warnline In some of the operations made in GiD by the user GiD gives information about what is expected to do by the user This information is very useful the first times GiD is used as a guideline for the user The place were GiD shows this kind of information is the lower part of its main window Select entities to draw its label Added 1 new points to the selection Enter more points ESC to leave 4 m 2 1 3 Command line Using GiD sometimes the user is asked to introduce data with the keyboard The Command line must be used for this purpose It is placed in the lower part of GiD window Command 2 1 4 Status bar The Status amp Information bar located at lower part of GiD s Window provides basic information at a quick glance Status amp Information foom 1x Modes 2K Elements LOK Render Normal Lay
46. Rotate In the Rotate part of the View menu also present in the right mouse button menu there are the options to rotate the view of the model A user friendly way of rotating is to move the mouse while its left button and the Shift key are pressed The corresponding icon for rotating the model is the following one 2 4 3 1 Set center of rotation An interesting option for rotating the view of the model is to set the center of rotation To change it 1 Select View gt Rotate gt Center from top menu or Rotate gt Center from right button mouse menu Then the cursor changes into the selection mode 2 Select an existing point of the model 3 Now rotate the model and check that the center of the rotation is the one selected 2 5 Layers and groups A really useful way for organizing the different parts of the model is using Layers 1 Open the Layers window by selecting the Utilities gt Layer and groups option or clickingS zin the upper icons toolbar The following window should raise up Layers and groups Double click here to integrate the window As it can be read in the upper part of the window if user double click on that part the Layers window is integrated in GiD window User can choose to work with the Layers and groups window integrated or not All the actions related with layers and groups can be accessed by clicking the right mouse Layers and groups 11 button onto t
47. abel shows the node number and the value of the result 3 Select View results gt No Results Show Min Max 130 8 3 8 Stream lines Menu View results gt Stream Lines With this option you can display a stream line or in fluid dynamics a particle tracing ina vector field Note stream lines are confined in a single volume mesh i e they do not jump from one Stream lines 131 volume mesh to the next volume mesh even if they are close neighbours In the provided example there are three volume meshes and stream lines will not cross the volume boundaries You can join the volume meshes into a single volume mesh using Utilities gt Join gt Volume sets Then you can delete the three separate volumes and switch the Single joined volume mesh on The above image results from doing this tutorial with the three separated volumes The image at the end of this stream lines tutorial is achieved if following step is done before the enumerated stream lines tutorial steps Select Utilities gt Join gt Volume sets to create a single volume mesh and delete the three other volume meshes V volumes V cil and V wake The above image results from 1 Select View results gt Default Analysis Step gt RANSOL gt 103 0 throught the menu bar or clicking on EE 2 Select View results gt Stream Lines gt Along line gt Velocity m s throught the menu bar With this option you can define a segment along which several st
48. al Ge ar m1 ee 7 7 EPE a F oy eT 3 pp A o Ty y Fo uc ae Re 7 ss ion A AT Si 7 Paii DE he Bid wet ee ge a ens 3 xX Sf rz lt i ap DB T i ate es Ps ja T ra ika EA aia N a yl Laren LPG Satis pA in Eat aE roel ee i a ORK RCANIO SEP A Ge ee oUt citien ESE RAS s at mT ey ASS jad The ho peer y 1 a k ee eal ma a Figure 31 Mesh visualized with the Mesh gt View mesh boundary option 6 Visualize the mesh generated with the various rendering options in the Render menu located in the mouse menu Generating a coarse mesh 64 Figure 32 Mesh visualized with Mesh gt View mesh boundary combined with Render gt Flat 7 Choose View gt Mode gt Geometry to return to the normal visualization NOTE To visualize the geometry of the model use View gt Mode gt Geometry To visualize the mesh use View gt Mode gt Mesh 4 5 2 Generating the mesh with assignment of size around points 1 Choose View gt Rotate gt Plane XY Original This way we will have a side view and View gt Mode gt Geometry and Render gt Normal to see the geometry like the image Figure 33 Side view of the part Generating the mesh with assignment of size around points 65 2 Choose Mesh gt Unstructured gt Assign sizes on points A window appears in which to
49. al sense which is counter clockwise 3 degrees equates to a clockwise rotation of 3 degrees 4 Enter the point 0 0 0 under First Point This is the point that defines the center of rotation 5 Click Select to select the surface that is to rotate which in this case is that of the circle 6 Press ESC or Finish in the Move window to indicate that the selection of surfaces to rotate has been made thus executing the rotation Rotating the circle 3 degrees around a point 47 Entities type Surfaces Second point Nurm Do extrude No Create contacts Maintain layers Multiple copie Figure 5 The move window 4 2 5 Rotating the circle 36 degrees around a point and copying it 1 Use the Copy window located in Utilities gt Copy 2 Repeat the rotation process explained in section Rotating the circle 3 degrees around a point pag 46 but this time with an angle of 36 degrees Rotating the circle 36 degrees around a point and copying it 48 Figure 6 Result of the rotations td NOTE The Move and Copy operations differ only in that Copy creates new entities while Move displaces entities 4 2 6 Rotating and copying the auxiliary lines 1 Use the Copy window located in Utilities gt Copy Rotating and copying the auxiliary lines 49 Entities type Lines Transformation Rotation First point Num x x eje Two dimensions Second point Num x 0 0 y 0 0 Collapse Do extrude Wo
50. an if using the previous option Generating a structured mesh surfaces LS e n Sot S J SS AATA S aA pdt Ppa Tur ki 1 a F ie gt ee I fe a a En n a aF p SS ee Pie He SEAvi Eng YE re ae aan rer ee 3 iS E m on m F E p A l E L 7 os am ef zW E R a E E E E m z 7 i a eg H i n m Tu Ta Em m E E d i aan u 7 n M i Py z E g e a 7 a s a E g NY a i E an E F E P a i E a a My cr a 8 i ot a ae 5 m m hy ee E m p at i m i oe i m 7 m jei m z E a a ae u a SADA E a oO E g x of a EN et aera Sach ee a ee 7 Tips 27 Ro bet 8 ECTE eee j 5 No i j Se E eT oar ry 5a re r no oF AA AZT SEP Se a aR T _ 7 SIZE TE SR e a yee Aa Figure 8 Structured mesh of quadrilateral and triangular elements on surfaces with the option Symmetrical structured triangles not set gt When selecting a line GID automatically selects all lines parallel to it 7 2 6 Generating structured meshes volumes 1 To mesh volumes with a structured mesh select the option Mesh gt Structured gt Volumes gt Assign number of cells 2 Select volumes 1 and 2 and press ESC a z E en 105 3 A window appears in which to enter the number of divisions that the lines to be selected will have Enter 6 and click Assign 4 Select lines of
51. art points will be chosen The number of points will also be asked for including the ends of the segment In the case of just one start point this will be the center of the segment dg NOTE This action could also be done clicking ons 2in the icon bar In this case we have to select the way to define the start point through the mouse menu In this case select Contextual gt Along line We want to create several stream lines along the model doing 2 lines 3 Write the initial point in the command line 10 15 3 4 Write the final point in the command line 10 15 3 5 You are asked for the number of points along the line Enter 5 and click Ok Note You can also press Ctrl t to set the cursor in the command line The first line with 5 stream lines is created 6 Write the initial point in the command line 10 15 7 7 Write the final point in the command line 10 15 7 8 You are asked for the number of points along the line Choose 3 The second line with 3 stream lines is created 9 Click the middle mouse button or press the Esc key in order to finish the operation Stream lines 132 m Stream line options Quality Quick Nice Type points ribbons 4 sided prisms S ize Scam Sie 1 0 Bil Color O Monochrome Stream contour filled Swirl Initial swit 0 0 pi r Arrows Show Arrows Color Size Spacing Result contour filled Several configuration options can be
52. art1 as layer to use to create the new volume in this layer 4 Choose Geometry gt Create gt Volume gt By contour and select all the visible surfaces to define the volume Press ESC to conclude the selection process 5 Choose Render gt Smooth to visualize a more realistic version of the model Creating the final volume 80 Figure 19 A rendering of the finished piece of equipment 5 5 Generating a mesh Now that the model is finished it is ready to be meshed Generate a coarse mesh is a good test to check that the model is correct and is valid to be used in a numerical simulation We will use default meshing settings 1 Choose Mesh gt Generate mesh 2 A window opens in which to enter the edge size of the mesh to be generated Seta value of 5 units and click OK 3 When the meshing process is finished a window appears with information about the mesh press View mesh in order to be showed Generating a mesh Figure 19 The volume mesh of tetrahedra 81 ASSIGNING MESH SIZES 82 6 ASSIGNING MESH SIZES ASSIGNING SIZES TO THE ELEMENTS OF A MESH 83 The objective of this example is to mesh a mechanical piece using the various options in GiD for assigning sizes to elements and the different surface meshers available In this example a mesh is generated for each of the following methods for assigning sizes using different surface meshers Assigning sizes around points Assigning sizes around lin
53. at are intersecting Figure 14 The inner surfaces to be intersected 4 Repeat the process with the three outer surfaces of the pipes that are intersecting Now the intersection lines are created and some surfaces are splitted by these lines 5 3 4 Deleting surfaces and close a volume 1 Choose Geometry gt Delete gt Volumes and select the two volumes to be able to delete some of its unwanted surfaces 2 Choose Geometry gt Delete gt Surfaces and select the small surfaces inside the first pipe Select Lower Entities in the contextual menu to delete its dependencies also Press ESC to conclude the process of selection Deleting surfaces and close a volume 78 Figure 15 Surfaces to be deleted 3 Use Geometry gt Create gt Volume gt By contour and select all surfaces ab es f Xx i r TH ge ae Ha oN N Sc A a a a i Figure 16 The volume of a T junction 4 From the Files menu select Save to save the file Enter a name for the file and click Save 5 4 Importing the T junction to the main file The two parts of the model have been drawn Now they must be joined so that the final volume may be created and a mesh of the volume may be generated 5 4 1 Importing a GID file 1 Choose Open from the Files menu Select the file where the first part created in section Creating a component part pag 70 was saved Click Open 2 Choose Files gt Import gt Insert GiD model from the menu
54. at contains the postprocess information so the steps to follow are 1 Start GiD 2 Switch to postprocess mode lt or Files gt Postprocess 3 Open the model with Files gt Open Ctrl o or clicking on 8 2 Changing mesh styles 1 Select Window gt View style 2 Select all the layers 3 change the style to Boundaries 4 Play a little with the options of these windows but to continue the tutorial let a Boundaries style selected for all meshes 5 Change render mode to Normal Changing mesh styles 117 Double click here to integrate the window Volumes Surfaces Cuts alphabetic order C Name V volumes V cil V wake oO t Elements 717 793 tetrahedrons 96 000 tetrahedrons 1 101 460 tetrahedrons 25 556 triangles 1 414 triangles 1 760 triangles 7 436 triangles 6 400 triangles 8 800 triangles 21 584 triangles 21 720 triangles I 5 volumes 1 Triangle inlet outlet 5 lateral interior cil 5 ext cil Sup 5 down O 0 BB Z Rename _ H eg Global settings Preprocess information Style Boundaries Show conditions None Render Smooth Draw mode Mone Model render Normal EEEE E b j dD D oO oe D oh p D Oop 0 0 0 0 0 0 0O 00 60 G mgn gn gn Be gn gn En gn gn gn iin I Culling No 8 3 Viewing the results In the example several results have been calculated for several time steps You can check these results thr
55. ate a surface mesh in which the elements are presented uniformly the user can select the option for a structured mesh This guarantees that the same number of elements appears around a node and that the element size is as uniform as possible To generate this type of mesh choose Mesh gt Structured gt Surfaces gt Assign number of cells Using this command the user should first select the 4 sided NURBS surface that will be defined by the mesh and press ESC Then a window appears where the number of subdivisions for the surface limit lines should be entered Enter value window Enter number of cells to assign to lines Enter 10 and click Assign and select one of the horizontal lines the parallel line is also selected Press ESC The same window appears again click Assign and select one of the vertical lines the parallel one is also selected Press ESC Click Close when the window appears again 1 Select 10 2 Select 10 divisions for the more divisions for horizontal lines the vertical lines The number of divisions can be checked selecting Mesh gt Draw gt Num of divisions To exit this visualization mode press ESC Creation and meshing of a surface 33 Num of divisions w NOTE GiD only generates structured meshes for surfaces of the type 4 sided surface or NURBS surface When this has been done the mesh is generated in the same way as the unstructured mesh by choosing Mesh gt Generate mesh Erase the old
56. ayer 54 Figure 14 Lines to be selected 4 2 10 Deleting the aux layer 1 Select the profile layer and set it off Click on the light bulb icon 8 Choose Geometry gt Delete gt All Types or use the GiD Toolbar Select all the lines and surfaces that appear on the screen Press ESC to conclude the selection of elements to delete Select the aux layer and delete it Click in the icon 6 Select the profile layer and set it on uBR U N Mi NOTE To cancel the deletion of elements after they have been selected open the mouse menu go to Contextual and choose Clear Selection Md NOTE Elements forming part of higher level entities may not be deleted For example a point that defines a line may not be deleted Md NOTE A layer containing information may not be deleted First the contents must be deleted 4 2 11 Rotating and obtaining the final profile Rotating and obtaining the final profile 55 1 Make sure that the activated layer is the profile layer Use the option To use 2 In the Copy window select the line rotation Lines Rotation 3 Enter an angle of 36 degrees Make sure that the center is point 0 0 0 and that you are working in two dimensions 4 In the Multiple Copies box enter 9 This way 9 copies will be made thus obtaining the 10 teeth that form the profile of the model 9 copies and the original 5 Click Select and select the lines defining the profile Press the ESC
57. both volumes parallel to the X and Z axes GiD automatically selects all the lines in each volume parallel to these in order to create the structured mesh Press ESC 5 Another window appears in which to enter the number of divisions on the lines Divide the lines parallel to the Y axis into 8 segments Enter 8 and click Assign 6 Select an edge of volume 1 or 2 parallel to the Y axis and press ESC Again the line division window comes up Since we have already finished the assignments click Close 7 8 9 Generating structured meshes volumes 106 Figure 9 Structured volume mesh of hexahedra an tetrahedra For structured volumes GiD generates tetrahedron meshes by default but hexahedron structured meshes can also be assigned Let s assign the element type that we wish to volume 1 and 2 Select Mesh gt Element type gt Tetrahedra then select volume number 2 and press ESC Select Mesh gt Element type gt Hexahedra then select volume number 1 and press ESC Select Mesh gt Generate mesh A window appears asking whether the previous mesh should be eliminated Click Yes 10 Another window comes up in which to enter the maximum element size Leave the 11 default value unaltered and click OK The result is the mesh shown in Figure 10 GiD can obtain volume structured meshes made of hexahedra tetrahedra or prisms As can be seen in Figures 9 and 10 there are two kinds of tetrahedron structured mesh the
58. c center of the element is calculated coinciding with the center of gravity and the coordinates are stored in the x_Cgi and y_Cgi variables The numerator sums are calculated When the loop is finished the following sums are stored in the x_num and y_num variables Finally the result of dividing the x_num and y_num variables by the den variable is stored in the x_CG and y_CG variables voLd output char filename 1024 FILE fp fplog double v The output function creates two files post res and log The results to be visualized in GiD Post process are stored in the post res file It is this file that stores the data which enables GiD to represent the distance of each point from the corresponding center of mass The numerical value of the center of mass is saved in the log file The accuracy of this value is directly proportional to the element size The main program 183 writing log information file strcpy filename projname strcat filename log folog fopen filename w fprintf fplog CMAS2D routine to calculate the mass center fprintf fplog project s projname pein tolog Mass Cenlers oli x1 x CG y CG fclose fplog Creating the log file the log extension is added to the project name and a file is created that will contain the numerical value of the position of the center of mass which in turn is stored in the x_CG and y y_CG variables of the program Creati
59. called from the cmas2d win bat file and has as parameter the name of the project This name is stored in the variable projname The main program calls the input calculate and output functions The input function reads the dat file generated by GiD The dat file contains information about the mesh The calculate function read and processes the data and generates the results The output function creates the results file void input char filename 1024 fileerr 1024 saul 1024 sau2 1024 EILE fp Terr int aux J error 0 void jumpline PILE strcpy filename projname strcat filename dat fp fopen filename r The first part of the input function links the project name with the dat extension thus obtaining the name of the file that is to be read This file is opened in order to be read The jumpline FILE function is declared This function simply reads a line from the file that it receives as a parameter It is used to jump lines of the text when reading the dat file for 1 0 2 67 itt Fumpline fo fscanf fp sd cd amp Nelem amp Nnod The first six lines of the dat file are jumped over since these are lines of information for the user see bas file Then the total number of elements and nodes of the project are read and stored in the variables Nelem and Nnod respectively x double malloc Nnod 1 sizeof double 1f x NULL error 1 y double malloc Nnod
60. can import the selecting Files gt Import gt Graph 28 Select Options gt Graphs gt Clear graphs in order to delete all the graphs 8 4 Creating images Menu Files gt Page and capture settings Creating images 138 Finally we will take some snapshots of our model You can save images in several formats The properties of the image resolution size etc can be assigned in Page and capture settings option Select Files gt Page and capture settings Check the Auto crop image option in order to cut the image in the model limits Click on Set Page button Click on Close button page and capture etn OOO Top 12 7 KR WN e Bottom 12 7 Image size width x height 266 5 x 184 6 mm 880 x 610 pixels Ag ndscape 297 Resolution Screen White background on images White background orm C Transparent background on images C Transparent background on animations C Don t save transparency layer on images Draw background images on images Draw background images on animations Menu Files gt Print to file This option asks you for a file name and saves an image in the required format with the defined properties in Page and capture settings Select Files gt Print to file gt PNG throught the menu bar Choose the location where you want to save the image Choose a name for the file Click on Save button 1 2 3 4 qd Creating images 139 NOTE This action could also be done by
61. chosen Enter 0 5 and click Assign 3 Select the lines defining the base of the prism i e lines 1 2 3 4 and 40 4 Press ESC to indicate that the selection of lines is finished and Close the window 5 Then gnerate the mesh again with the same general mesh size as before Assign size to lines 89 6 This results in a high concentration of elements around the chosen lines given that the selected element size 0 5 is much smaller than that of the rest of the elements in the model see Figure 7 Loy tabs Pe Ba E soe BARES Gn at OR AY N Se RN oi ae A QS ay VIANA V AA Y Figure 7 Mesh with a concentration of elements around lines 6 2 4 Assign size to surfaces Now we are going to set a specific mesh size tto the triangular surface resulting from the section of one of the vertexes of the prism surface number 1 1 To detect the surface one the Label option can be chosen but also the Signal one see Signal pag 17 2 Select Mesh gt Unstructured gt Assign sizes on surfaces In the window that appears enter the size of the elements to be assigned on the surfaces that will be chosen Enter 0 5 and click Assign 3 Select surface number 1 press ESC and Close the window 4 Generate again the mesh with the same general mesh size 5 This results in a high concentration of elements on the choosen surface due to the value selected 0 5 see Figure 8 Assign size to surfaces
62. computer disk drive and select the location in which to save the file Once the desired directory has been selected the name for the current project can be entered in the space titled File Name Save it as initiation gid GD Save Project Directory ES test No Preview E P Filename initiation gid Files of type GiD project gid gg NOTE Next the manner in which GiD saves the information of a project will be explained GiD creates a directory with a name chosen by the user and whose file extension is gid GiD creates a set of files in this directory where all the information generated in the present example is saved All the files have the same name of the directory to which they belong but with different extensions These files should have the name that GiD designates and should not be changed manually Each time the user selects option save the database will be rewritten with the new information or changes made to the project always maintaining the same name To exit GiD simply choose Files gt Quit To access the project that we have just created simply open GiD and select from the Top Menu Files gt Open An Auxiliary Window will appear which allows the user to access and open the directory initiation gid Creation and meshing of a surface 28 3 3 Creation and meshing of a surface We will now continue with the creation and meshing of a surface First we will create a second line
63. d CondNumeEntities to the NFIX variable an int variable NFIX returns the value of the NFIX variable Potentials Prescrits Node Tipus Valor Etiqueta loop nodes OnlyInCond NodesNum cond 1 end This provides a rundown of all the nodes with the condition Point Weight with a list of their identifiers and the first weight field of the condition in each case loop nodes OnlyInCond executes a loop that will provide a rundown of only the nodes with this condition cond 1 returns the number 1 field of a condition previously selected with the set cond command The field of the condition may also be selected using the name of the condition for example cond weight cmas2d bas Creating the Data Format File Template file 170 oV o o o o o o Vo VoV o Problem Size oV o o o Vo Vo o o Vo o o Y o Vo Yo o Yo Yo Yo o Yo Yo Yo Yo o Yo Yo Number of Elements amp Nodes nelem npoin o o o o Vo o o Vo o o V Mesh Database o Yo Yo Yo Yo Yo Vo o Vo Vo Yo Yo Yo o Yo Vo Yo Yo VY Yo o Yo Yo Yo Yo Yo Yo Coordinates Node X Y set elems all loop nodes format 5i 14 5e 14 5e NodesNum NodesCoord 1 real NodesCoord 2 real end nodes Connectivities Element Node 1 Node 2 Node 3 Material loop elems format 10i 10i 10i 10i 10i ElemsNum ElemsConec ElemsMat end elems Begin Materials N Materials nmats Mat Density loop mate
64. d in the Ncnd variable The nodes associated with a condition are read and stored in the nodc table indexed by the condition identifier The value of the condition is stored in wval another table indexed by the condition identifier void calculate double v auxl aux2 aux3 int nl n2 13 int mat double x CGi y CGI double x num 0 y num 0 den 0 This is the function that calculates the center of mass Declaration of the local variables used in calculate for 1elem 1 ielem lt Nelem ielem nl N 0 i1elem 1 3 n2 N 1 ielem 1 3 n3 N 2 i1elem 1 3 Calculating the volume volume is the area for surfaces The main program 182 v fabs x nl y n2 x n2 y n3 x n3 y nl x nl y n3 x n2 y nl x n3 y n2 2 x CGi x ni x n23 x n3 3 y_CGi y nl y n2 y n3 3 mat imat ielem x num rhoma t vtz CG1 y numt rho mac v y Col dent rho mat v puntual weights for 1cnd 1 icnd lt Ncnd icnd tt inod nodc licnd x n mi wval icnd x inod y numt wval icnd y inod dent wval icnd x CG x num den y CG y_num den The identifiers of the nodes of the present element are saved in n1 n2 n3 This loop makes a rundown of all the elements in the mesh The volume is calculated for each element Here the volume is the area provided we are dealing with 3D surfaces The volume calculations are stored in the v variable The geometri
65. defining the contourand press ESC Correcting surfaces and creating a conformal mesh 153 result surface 5 Visualize the mesh again View gt Mode gt Mesh You will see the previous mesh the mesh its not recomputed If you want to see the results of the first correction the mesh must be regenerated with Mesh gt Generate mesh 6 Use View gt Higer entities gt Edges on mesh mode and magnify the zone indicated HigherEntities 2 Interior 1 Boundary Second part to repair 7 Select View gt Mode gt Geometry In this example the situation involves a contour of four lines that does not correspond to any real surface of the piece These lines were too far apart to be collapsed 8 Select Geometry gt Create gt NURBS surface gt By contour Select the lines Press ESC twice Correcting surfaces and creating a conformal mesh 154 LMA ff FF 1 i 1 ti i TE iz iN 1 i paee ff i O aa Hl N ii AA ee 14 i L A mn i i h a i i i p al i p i AT i I l l l i i i i i I J ou i A Ami ha TOAN LiT 1 5 ee _ a T L 4 EA i l i l Yon a 4 on k Y YA k AN yt i i K k yy ty i wa 1 1 1 ae i MW AN ONAL NO an 1 g NA AS k a 1 i i b i ec A i Ss he ae ee i ee a Sa r hs a na 4 7 a oo i Ys ae mO od 1 aco ey Tz Le Ps ey i Hii in T oan i t E maan b r z ga i Contour l
66. dified manually HigherEntities 2 Interior 1 Boundary Higher edges after collapsing 9 3 2 Correcting surfaces and creating a conformal mesh 1 With the option View gt Zoom In magnify the zone illustrated HigherEntities 2 Interior 1 Boundary Zone in the mesh to zoom in 2 Select View gt Mode gt Geometry to visualize the geometry of the piece Correcting surfaces and creating a conformal mesh 152 The zone in geometry mode There is a rectangular surface that does not fit within the boundaries of a rounded corner surface a hole in this case We will suppose that the problematic surface is planar This way it can be erased and recreated in order to fit the rounded corner boundary 3 Select Geometry gt Delete gt Surfaces Select the problematic surface but before pressing ESC Go to Contextual menu and select Lower Entities With this option the surface and ines and points that belongs to only this surface will be deleted oN r ae Image to clipboard Deleting surface and its lines and points 7 Remove From Selection Zoom gt ma F Invert Selection Clear Selection m Pan i Selection Window gp Redraw Send Lay To Use Render Connected Tangent Label Tolerance Tangent Angle Layer gt Parents Of Switch full screen F11 Children Of r _ i J Escape 4 With Geometry gt Create gt NURBS surface gt By contour create a new surface Select the lines
67. e center of an arc Contextual menu 6 Contextual Zoom p Rotate Pan aan Redraw Render Label Layer of Switch full screen F11 Image to clipboard 2 1 6 Escape function An important thing a GiD user should know as a general philosophy of use of the program is the Escape key functionality In almost all the actions performed by the user to declare the action as done the user should press Escape key or press the center mouse button 2 2 Load a model In the Files menu user can find the typical operations for managing the GiD projects like save a project open an existing project import and export files print or quit the program Most of this options are also accessible from the icons toolbar The corresponding icon is shown in the menu next to the option 1 Click on Files gt Open and select the GiD model gid_model_basic gid GiD also can load a model just with drag amp drop The following model should be loaded Load a model 7 2 3 Render modes In the View menu user can find the Render options They are also accessible from the right mouse button and the status bar 1 Select View gt Render gt Normal In Normal render mode user can see the entities drawn in different colors depending on the kind of entity volumes in light blue surfaces in pink lines in blue and points in black as it can be seen in the following figure Render modes 8 x AN X Ki ri fi f vehi an
68. e nodes of the mesh listing their identifiers and coordinates loop end commands used to indicate the beginning and the end of the loop The command loop receives a parameter loop nodes the loop iterates on nodes loop elems the loop iterates on elements loop materials the loop iterates on assigned materials format the command to define the printing format This command must be followed by a numerical format expressed in C syntax NodesNum returns the identifier of the present node NodesCoord returns the coordinates of the present node NodesCoord n real returns the x y or z coordinate in terms of the value n n 1 returns the x coordinate n 2 returns the y coordinate n 3 returns the z coordinate Connectivities Element Node 1 Node 2 Node 3 Material xset elems all loop elems format el0QislOisel0isloi1cloi ElemsNum ElemsConec ElemsMat xend elems This provides a rundown of all the elements of the mesh and a list of their identifiers the nodes that form them and their assigned material set elems all the command to include all element types of the mesh when making the loop Creating the Data Format File Template file 168 ElemsNum returns the identifier of the present element ElemsConec returns the nodes of an element in a counterclockwise order ElemsMat returns the number of the assigned material of the present element Begin Materials N Materials nmats This
69. each lens a chromatically opposite color usually red and cyan Anaglyphic images are made up of two color layers superimposed Since the glasses act as red and cyan filters we should be careful with the model s colors To avoid problmes we will change the contour fill color scale 1 Select Options gt Contour gt Color Scale gt 3D Anaglyphs 2 Select View gt Advanced viewing settings 3 Check the Use stereo option Stereo mode 3D 129 4 Check the Dynamic update option in order to change the options without the need to click the Apply button Set the eye distance to the value where you can see the 3D effect Unheck the Use stereo option Close the window Select View results gt No Results Change the view style to boundaries for all the layers like in Changing style chapter O ON OA UW Pressure Pa 0 55696 0 49507 0 43319 0 37131 0 30942 0 24754 0 18565 0 12377 0 061884 b Y step 103 Contour Fill of Pressure Pa 8 3 7 Show Min Max Menu View results gt Show Min Max With this option you can see the minimum and maximum value of the chosen result in the chosen analysis step In our case we will choose the Vy component of velocity result for the first analysis step 1 Select View results gt Default Analysis Step gt RANSOL gt 91 5 throught the menu bar or clicking on EE 2 Select View results gt Show both gt Velocity m s gt Vy throught the menu bar or clicking on AN The l
70. ection CA Figure 21 The lines that form the octagon 4 Select the profile layer and set it Off Creating the volume of the prism 59 4 4 2 Creating the volume of the prism 1 First copy the octagon a distance of 50 units relative to the surface of the wheel which is where the base of the prism will be located In the Copy window choose Translation and Lines Since we want to translate 50 units enter two points that define the vector of this translation for example 0 0 O and 0 0 50 Make sure that the Multiple Copies value is 1 since the last time the window was used its value was 9 2 Choose Select and select the lines of the octagon Press ESC to conclude the selection Figure 22 Selection of the lines that form the octagon 3 Since the Z axis is parallel to the user s line of vision the perspective must be changed to visualize the result To do this use the Rotate Trackball tool which is located in the GiD Toolbox and in the mouse menu or press lt Caps gt key and drag the righ mouse button to rotate the view Figure 23 Copying the octagon and changing the perspective 4 Choose Geometry gt Create gt NURBS surface gt By contour Select the lines that form the displaced octagon and press ESC to conclude the selection Again press ESC to exit the function of creating the surfaces Figure 24 The surface created on the translated octagon 5 In the Copy window choose Translatio
71. eerr w tprintf terr ERROR Elements with no materialii Jy fclose ferr exit l i The connectivities are read and the N variable is saved This variable is a Nelem x 3 size table with two fields The nodes assumed triangles of 3 nodes forming the element are saved in the first field The element identifiers are saved in the second one All the elements are checked ensuring that they have been assigned a material If the identifier of the material is O meaning that no material has been assigned to the element an err file is created containing information about the error and the program is aborted for 1 0 i lt 57 i Jumpline fp LScani ip ss 2s lt d Saul sSauZz amp Nmar for 1 0 i lt 3 7 i jJumpline fp The main program 181 reading density of each material for 1 1 i lt Nmat itt tocant ip od cli Saux LDO weading conditions for 1 0 1 lt 4 i jumpline fp fecani tip sad lt Ncnd for i 0 i lt 6 i jumpline fp for icnd 1F t end lt Ncnd acndt rescant fp ed cli enode icnd amp wvaliicnd y jumpline fp fclose fp Reading the remaining information in the dat file The total number of materials is read and stored in the Nmat variable The density of each material are read and stored in the rho table The material identifier indexes the densities The total number of conditions is read and store
72. el 5 The GiD collapse depends upon the Import tolerance Two entities are collapsed converted into one when they are separated by a distance less than the Import tolerance parameter To test this enter a new value for the Import tolerance parameter 6 Goto Utilities gt Preferences and select Import and Export branch Uncheck the Automatic import tolerance value and enter 0 15 for the Import tolerance value Click Apply mu am EF General Import 5 Interface Automatic collapse after import Other Et Graphical Appearance Colours Collapse Ignoring layers Each layer separately System IGES Curve on surface from 30 Meshing C IGES Create all in layer to use Automatic import tolerance value C Import tolerance 0 15 Main Export Other Boundary layer Cartesian mesher z Sphere mesher 5 Import and Export gt Fonts Grid s Postprocess IGES B Rep output style The preferences window Global collapse of the model 151 7 Select Geometry gt Edit gt Collapse gt Model 8 A dialog window appears to confirm the seletion Click Ok 9 Select Mesh gt Generate Erase the old mesh and use the default element size 10 Visualize the results with View gt Higher entities gt Edges Some of the contiguous surfaces in the interior of the model have now being joined However there are still some surfaces that prevent the mesh from being completely conformal These surfaces must be mo
73. elect Mesh gt Generate Mesh 4 A window opens asking whether the previous mesh should be eliminated Click Yes 5 GiD then asks you to enter the general maximum element size Leave the default value unaltered and click OK 6 Click View mesh in the pop up window to see the result Assign size to points Figure 4 Geometry of the model The point around which the mesh will be concentrated th Hh A mn f Ld hl 4 T J y ti p 5 AAN al iy aa all Ar Y i ae eg I iy ih at nat L AL Th Tai gr ety bi PATH EN fA a I AFT an Ean ai tii PE Wh pine i HAH VEF U l iyi a H AFTI i E Li ii eat Tk RITH 4 ib 4 Ui hij ie ay Lint i 1 t H PH LAR ay ay tiri AUH T i yh AUER Ht 4 j HAI j Mik 1 i Ke ABa a0 ANI UTRHL AFEA a 14 tl IAA i aaa i ar TRH EE See AA Th L e nes ii th i ae SETRI 64 A it e g NA fT AL ae 7 Ly ih i y MA 11 f whi i 4 IVAI t 11 p ft ay i vi d f Figure 5 The mesh with a concentration of elements around the point 7 A concentration of elements appears around the chosen point given the selected size 0 1 of these elements see Figure 5 One can control the way the size of the elements changes from a finer to a coarser region 8 Go to Utilities and open Preferences window In the Meshing branch there is the option Unstructured Size Transitions This option defines the transition gradient of element siz
74. elect Surfaces and Rotation Enter an angle of 180 degrees Since the rotation may be done in 2D choose the option Two Dimensions The center of rotation is the upper right point of the pipe elbow Make sure the Do Extrude menu is set to No 2 Click Select and select the surfaces that join the two pipe sections and press ESC 3 Select Utilities gt Move window select Surfaces and Translation The points defining the translation vector are circled in next figure Figure 8 The circled points define the translation vector 4 Click Select and select the surfaces created in point 1 Press ESC The result should be as is shown Creating the end of the pipe 7 Figure 9 The final position of the translated elbow 5 To create a ring surface choose Geometry gt Create gt NURBS Surface gt By contour and select the four lines that define the opening of the pipe see next figure Press ESC twice Figure 10 Opening at the end of the pipe From the Files menu choose Save in order to save the file Enter a name for the file and click Save 5 3 Creating the T junction Now an intersection composed of two pipe sections will be created in a separate file Then this file will be imported to the original model to create the entire piece 5 3 1 Creating one of the pipe sections 1 Choose Files gt New thus starting work in a new file 2 Rename the layer LayerO to pipe1 and create two new childs layers inner and
75. eleting surfaces and close a volume 5 4 Importing the T junction to the main file 5 4 1 Importing a GID file 5 4 2 Creating the final volume 5 5 Generating a mesh 6 ASSIGNING MESH SIZES 6 1 Introduction 6 1 1 Reading the initial project 6 2 Element size assignment methods 6 2 1 Assign general mesh size witth default options 6 2 2 Assign size to points 6 2 3 Assign size to lines 6 2 4 Assign size to surfaces 6 2 5 Assignment following chordal error criterion 6 3 Rjump mesher 6 3 1 RJump default options 6 3 2 Force to mesh some entity 7 METHODS FOR MESH GENERATION 7 1 Introduction 7 1 1 Reading the initial project 7 2 Types of mesh 7 2 1 Generating the mesh by default 7 2 2 Generating the mesh using circles and spheres 69 70 70 70 71 72 73 75 7o 76 Z7 77 78 78 79 80 83 83 83 84 85 86 88 89 90 91 92 93 97 97 97 98 99 100 Table of Contents 7 2 3 Generating the mesh using points 7 2 4 Generating the mesh using quadrilaterals 7 2 5 Generating a structured mesh surfaces 7 2 6 Generating structured meshes volumes 7 2 7 Generating semi structured meshes volumes 7 2 8 Concentrating elements and assigning sizes 7 2 9 Generating the mesh using quadratic elements 8 POSTPROCESSING 8 1 Loading the model 8 2 Changing mesh styles 8 3 Viewing the results 8 3 1 Iso surfaces 8 3 2 Animate 8 3 3 Result surface 8 3 4 Contour fill cuts and limits 8 3 5 Combined results 8 3 6 Stereo mode 3D 8 3 7 Sho
76. ers 3 Off 1 3 8275 0 17304 0 From left to right you can find Zoom factor Current number of nodes and elements Click to acces to Status Window Status bar STATUS Project Name CA Users zero Desktop gid_model_basic Problem type UNKNOWN Using layer Layerll Num of nodes 27929 Num of elem 7506 Changes to save 0 1 2 Necessary to mesh again 0 1 0 nterval 1 of 1 intervals Degree of elernents is Normal Using now mode geometry mesh mesh number of points 80 number of points with 3 higher entities 64 number of points with 4 higher entities 16 number of points with 0 conditions 60 number of lines 128 number of lines with 2 higher entities 120 number of lines with 4 higher entities amp number of lines with 0 conditions 128 number of surfaces 64 4 Current renter mode Click to change render Number of layers in Pre number of sets in Post Mouse coordinates Click to open Coordinate window in Pre and Change result units in Post Current Mode Pre or Post 2 1 5 Contextual menu Clicking the right mouse button on GiD a popup menu will appear with options related to the clicked object When picking the main drawing space on the top appear Contextual that is filled with different commands depending on the current GiD state e g when asking for a point they appear options like Point in line to select a point over a line or Arc center to select the coordinates of th
77. es Assigning sizes on surfaces Assigning sizes with Chordal Error gee T N i ea ens ah aa TAS Se SOS Aa N77 SN SERS a RR 2 SS Se WK SSS SSS ESS Woes ZAN PEES WAN W p o ee d7 e a es AES a o fo Nee Ue 6 1 Introduction In order to carry out this example start by opening the project ToMesh4 gid This project contains a geometry that will be meshed using four different methods each one resulting in a different density of elements in certain zones 6 1 1 Reading the initial project 1 Open the project ToMesh4 gid 2 The geometry appears on the screen It is a set of surfaces 3 Change the render mode from the mouse menu or from the status bar and rotate the model in order to get a better perception of the geometry of the model 4 Finally return to the normal visualization selecting Render gt Normal This mode is Reading the initial project 84 more user friendly yA rA Figure 1 The geometrical model of ToMesh4 gid project 6 2 Element size assignment methods GiD automatically corrects element sizes according to the shape of the entity to be meshed and its surrounding entities This default option may be changed b
78. es Press ESC 7 Another window appears in which to enter the number of divisions on the lines In this case all the boundary lines have already been defined Therefore click Close 8 Select Mesh gt Element type gt Triangle Select surfaces 26 and 12 Press ESC 9 10 11 12 Generating a structured mesh surfaces 104 AX A i Sl vT e TE E S ey Ne Ech AIS B E g _ p Jo 7 E 5 s E g 8 a a m m E nm a mi E m 5 5 m m m T aan m 4 i gI a utag MY o R a m T a a i a g 4 i E u na 5 ak i m f 4a k i ae i E 5 m nm E g Ea a E P F a a m Figure 7 Structured mesh of quadrilateral and triangular elements on surfaces Select Mesh gt Generate mesh A window comes up asking whether the previous mesh sould be eliminated Click Yes Another window appears in wihich to enter the maximum element size Leave the default value unaltered an click OK The result is the mesh shown in Figure 8 As seen in Figures 7 and 8 GID can obtain surface structured meshes made of quadrilaterals or triangles There are tow kinds of structured mesh that use triangles the one shown in Figure 7 is obtained when the Utilities gt Preferences gt Meshing gt Main gt Structured Mesher gt Symmetrical structured gt triangles option is set If this option is not set the mesh presented in Figure 8 is produced with fewer nodes th
79. es size gradient whose values are between O and 1 The greater the size gradient the greater the change in space To test this enter the value 0 4 and click Accept 9 Again generate the mesh Mesh gt Generate Mesh with the same general mesh size Assign size to points 88 SVS NY REEDA ra AA SSSI RR PEEL OOk a N RSE KI EER WESE ee KN Z ce E Kj wa AN re Z m i i as Ve Ne A f _ IX O N KA Doe WY As ane S PS ZNA V mee _ i Wi Y Hey VAN SESS WEIS ORE SS ZAN SE EATA LK NY lt VACR USN SA 3 MSL NEE eC ay Wane iit Tae pena aa Figure 6 Mesh with the elements concentrated around a point with a size gradient of 0 4 10 The size gradient 0 4 results in a higher density around the point see Figure 6 11 Now go back and enter 0 6 in Unstructured Size Transitions This will result in a mesh more suitable for our objectives Click Accept be used Instead of pressing the ESC key the center mouse button or the mouse wheel can also 6 2 3 Assign size to lines We are going to set an specific mesh size to some of the lines 1 To see entity numbers select the Label option see Labels pag 15 Select all the lines in order to see their numbers 2 Select Mesh gt Unstructured gt Assign sizes on lines In the window that appears enter the size of the elements around the lines that will be
80. esult is drawn gt a MC DISTANCE factor The View Results window 16 Now choose the MC DISTANCE result and click Apply A graphic representation of the calculation is obtained Visualizing the distance MC DISTANCE from the center of mass of the objectto each element for an object of homogeneous material The results shown on the screen reproduce those we anticipated at the outset of the problem the center of mass of an object made of homogeneous material coincides with its geometric center The log file will provide the exact coordinates of this point 10 3 1 Executing the calculation with a concentrated weight Executing the calculation for an object of heterogeneous material and subject to external point weight 1 Choose the Files gt preprocess option to go back to preprocess 2 Change to geometry view mode by View gt Mode gt Geometry Executing the calculation with a concentrated weight 177 3 Choose the Data gt Conditions option A window is opened in which the conditions of the problem should be entered Point Weight Weight 0 Assign Entities Draw Unassign The conditions window 4 Enter the value 1e3 in the Weight box Click Assign and select the upper corner point Press ESC when this step is finished 5 Choose Mesh gt Generate 6 A window comes up asking whether the previous mesh should be eliminated Click Yes 7 Another window appears in which the maximum elemen
81. he Layers and groups window Most of them can be also used by the corresponding icon in the upper part of the Layers window By moving the mouse over the icons of the upper part of the window and staying 2 seconds onto an icon a help message is shown in order to give the user information about the action associated with the icon 2 5 1 Create a layer GiD allows to create a hierarchical structure of Layers so as a Layer can contain sub layers Let s create a Layer into another one as an example 1 Select using the left button of the mouse the Layer6 2 Select the New child option in the right mouse button menu or click Legin the upper part of the Layers and groups window Automatically a layer named Layer0 should appear as shown in the following figure C VO WU Tr Bie o 6 Layerll 7 oc p 2 5 2 Rename a layer To rename a Layer user should select the layer in the Layers and groups window and press F2 key or select the Rename option in the right mouse button menu Rename a layer 12 1 Select the LayerO 2 Rename it to Auxiliar Now the Layers window should look like the following picture u p a a u p 2 5 3 Change the color of a layer By clicking on the colored square next to each layer name the following window pops up allowing the user to change the color of the layer TT COO Base colors _ ty Ue te Che ERHET User colors ERREEN EEEN Ret 255 ff Gree
82. he mesh with the same default general mesh size 11 This results in a high concentration of elements in curved areas without the nodes in RJump default options 93 the lines and points that mesher skips Now our approximation is significantly improved see Figure 12 Fr F rE oo he el ses AA ih a a RANN Me ae a au D Tide td aH Mao Fin M l 7 Biber ae Ea E Bea e NA az E a A Co Figure 12 Mesh using the RJump mesher and assigning sizes by chordal error 6 3 2 Force to mesh some entity If there is a line or a point that the RJump mesher would usually skip but it is required for you to be meshed you can specify the entity so that it is not skipped As an example we will force Rjump to mesh line number 43 in order to concentrate elements around point number 29 as it was done in section Assign size to points pag 86 1 Select Mesh gt Mesh criteria gt No skip gt Lines and select line number 43 Press ESC 2 Select Mesh gt Draw gt Skip entities Rjump to display the entities that will and will not be skipped in different colors As is shown in Figure 13 line 43 will now not be Skipped the rest of the lines are unaffected and RJump will either skip or mesh them according to its criteria Force to mesh some entity 94 Rjump Skip No Skip Skip Figure 13 Entities that will be skipped and not skipped using the RJump mesher 3 Selec
83. hoosing the first option the Contour Limits window appears With this window you can set the minimum maximum value that Contour Fill should use Check the Min checkbox Change the value to 0 Click on the Apply button Click on the Close button Ui BR U N Outliers will be drawn in the colour defined in the Out Min Colour option In order to view it better we will change this color to transparent 6 Select Options gt Contour gt Min Options gt Out Min Color gt Transparent Pressure Pa 0 55696 0 49507 0 43319 O 3d 7131 0 30942 0 24754 0 18565 0 12377 0 061884 8 3 5 Combined results An interesting postprocess options is to combine several result visualizations like this one Combined results 127 Pressure Pa 0 55696 _ 0 49507 0 43319 O 3 7131 0 30942 0 24754 0 18565 0 1237 0 061864 o To get this view follow these steps 1 Clear all results visualizations with View Results gt No results or the icon T 2 Select Window gt Several results Then following window appears Several Results E3 Results views one by one one over another Current list of results Delete Delete all Id 5 No results 3 In this window select one over another With this option GiD is told to visualize one result over another 4 Select View Results gt Default Analysis Step gt Ransol gt 103 5 Select View Results gt Iso surfaces gt Exact gt
84. ill be erased 4 1 2 Creating two new layers 1 Open the layer management window This is found in Utilities gt Layers and groups 2 Create two new layers called aux and profile 3 Choose aux asthe activated layer From now on all the entities created will belong to this layer Double click here to integrate the window Layers Groups sK ea 7 C VO FU Tr E P T LayerO eg i profile d Figure 1 The layers window g NOTE You can also access to the layers information through the standard bar The layer in use is selected in the combobox aux amp Name C KVO WU Tr amp A men e Layer T od A be profile of A 4 2 Creating a profile In our case the profile consists of various teeth Begin by drawing one of these teeth which will be copied later to obtain the entire profile 4 2 1 Creating a size 55 auxiliary line 1 Choose the Line option by going to Geometry gt Create gt Straight line or by going to the GiD Toolbar 2 Enter the coordinates of the beginning and end points of the auxiliary line For our Creating a size 55 auxiliary line 45 example the coordinates are 0 0 and 55 0 respectively Besides creating a straight line this operation implies creating the end points of the line 3 Press ESC 3to indicate that the process of creating the line is finished Press ESC again to end the line creation function 4 If the entire line does not appear on the
85. ines that define the surface indicated 9 Visualize again higer entities View gt Higer entities gt Edges and magnify the zone HigherEntities 10 2 Interior Select View gt Mode gt Geometry 1 Boundary There are two surfaces that overlap each other at one end Correcting surfaces and creating a conformal mesh 155 The magnified zone with two overlapping surfaces In this case the best solution for correcting the boundary is to trim the overlap 11 Select Geometry gt Create gt NURBS surface gt Trimmed 12 Select the surface to be trimmed Then select the new boundary The surface to be trimmed and the new boundary Select Geometry gt Delete gt Surfaces Select the original surface Press ESC twice Correcting surfaces and creating a conformal mesh 156 The original surface to be deleted 14 Use Geometry gt Delete gt Lines and after delete the points with Geometry gt Delete gt Points to select the lines and points that belong to the surface that has been trimmed and which no longer belong to any surface In this case all the visible lines and ponints may be selected since the program will only eliminate those which do not have entities covering them Lines and point that no longer belong to any surface 15 Select Mesh gt Generate mesh Then visualize the result using the option View gt Higer entities gt Edges Correcting surfaces and creating a conformal mesh
86. is file will define the format of the dat text file created by GiD It will store the geometric and physical data of the problem The dat file will be the input to the calculating module Creating the Data Format File Template file 166 Md NOTE It is not necessary to have all the information registered in only one bas file Each bas file has a corresponding dat file Write the cmas2d bas file as follows The format of the bas file is based on commands Text not preceded by an asterisk is reproduced exactly the same in the dat file created by GiD A text preceded by an asterisk is interpreted as a command Example bas file 5355 Problem Size Number of Elements amp Nodes nelem npoin dat file 5355 Problem Size Number of Elements amp Nodes 5379 4678 The contents of the cmas2d bas file must be the following bas file Title GenData Title 6 666666666 66606066 Problem Size 665065656656 555S565565ES5ES55ESECSOES Number Of Elements amp Nodes nelem npoin In this first part of cmas2d bas file general information on the project is obtained nelem returns the total number of elements of the mesh npoin returns the total number of nodes of the mesh Creating the Data Format File Template file 167 Coordinates Node X Y loop nodes format 51 14 5e514 5e NodesNum NodesCoord 1 real NodesCoord 2 real xend nodes This command provides a rundown of all th
87. l in the mouse menu then select the option Join Ctrl a Point 17 is the point at which to make the cut Correcting surfaces 147 The zone after cutting line 2869 at point 17 3 Now that the lines are precisely connected a local collapse may be executed Select Geometry gt Edit gt Collapse gt Lines Then select the lines that appear on the screen and press ESC iz x The situation after collapsing the lines 4 After the collapse the surface boundary is correct and the surface may be drawn with the new boundary The labels are no longer needed so click Label gt Off in the mouse menu 5 Select Geometry gt Create gt NURBS surface gt Trimmed Select surface 124 Then select the lines defining the recently repaired boundary Press ESC twice Correcting surfaces 148 j cs TT we RN o ea FG Figure 11 Surface 123 with its new boundary 6 Select Geometry gt Delete gt Surfaces Select surface 124 and press ESC Figure 12 The surface to be eliminated 7 To begin the second example in this section mesh the geometry again with Mesh gt Generate Mesh 8 A window comes up in which to enter the maximum element size for the mesh to be generated Leave the default value provided by GiD and click OK The mesh generating process may be carried out with no further errors found Correcting surfaces 149 T eae DS ie RS hte Progress in mes Mesh generated Num of Triangle elermnents 12019
88. l t gt fclose ferr exit 1 j for i 0 i lt 5 i jumpline fp fSscant ip ss 2s 2d saul Sauz amp Nmar for i 0 i lt 3 i jumpline fp reading density of each material for 1 1 i lt Nmat i Scant fp sd cli Saux erhol i 7 reading conditions The main program 186 for i 0 i lt 4 i jumpline fp ESCani ip sd lt Ncnd for i 0 i lt 6 i jumpline fp for 1cnd l7 1cnd lt Ncnd iwcnd rscant ip sed oli enode icnd wvel acnd jumpline fp fclose fp void calculate double v int nl n2 nos int mary double x CCl y CG1 double x num 0 y num 0 den 0 for 1elem 1 ielem lt Nelem ielem nl N 0 ielem 1 3 n2 N 1 ielem 1 3 n3 N 2 ielem 1 3 Calculating the volume volume is the area for surfaces v fabs x nl y n2 x n2 y n3 x n3 y n1 x nl y n3 x n2 y nl x n3 y n2 2 x CGi lal x n2 4231 737 y Cer yinl brylaZia yin 7 37 mat imat ielem x n mt rhol mat v x CG1 y nums rho mat v y CG1 dent rho mat v puntual weights for 1icnd 1 1cnd lt Nend icndt inod nodc icnd x numt wval icnd x inod y numt wval icnd y inod den wvall icnd The main program 187 x CG x num den y CG y num den void outp t char filename 1024 FILE fp fplog double v writing log info
89. ll sizes Select a transition size of 0 8 to have a fast transition and then obtain few elements Click Apply 2 Choose Mesh gt Reset mesh data to delete the previously assigned sizes 3 Choose Mesh gt Unstructured gt Assign sizes on lines A window appears in which to enter the element size around the lines to be selected Enter size 0 7 and click Assign 4 Select only the lines of the wheel profile see next figure in the same way as in previous section and press ESC 5 The window appears again click Close to finish Generating the mesh with assignment of size around lines 67 Figure 37 Selected lines of the wheel profile 6 Choose Mesh gt Generate mesh A window appears asking if the previous mesh should be eliminated Click Yes 7 Another window opens in which the maximum element size should be entered Leave the last value unaltered and click View mesh 8 A greater concentration of elements has been achieved around the selected lines In contrast to the case in previous section this mesh is more accurate since lines define the profile much better than points do Figure 38 Mesh with assignment of sizes around lines IMPLEMENTING A COOLING PIPE 68 69 5 IMPLEMENTING A COOLING PIPE ADVANCED 2D amp 3D TECHNIQUES AND MESHING IMPLEMENTING A COOLING PIPE This case study shows the modeling of a more complex piece and concludes with a detailed explanation of the corresponding meshing process The piece
90. mesh and assign a general element size of 1 though in this case it is not necessary Creation and meshing of a surface 34 wI NOTE Another way to get the same result is using the option Mesh gt Structured gt Surfaces gt Assign size With this option we set the element size If we want to get 10 elements per line and the line measures 10 units we should set 1 as S Ze If we don t know how much measures a line we can use the option Utilities gt Distance and select the 2 points defining the line We can see here that the default element type used by GiD to create a structured mesh is a square element of four nodes rather than a three nodded triangular element To obtain triangular elements the user can specifically define this type of element by choosing Mesh gt Element type gt Triangle and selecting the surface to mesh as a triangular element Regenerate the mesh and the following figure is obtained Creation and meshing of a surface 35 GiD also allows the user to concentrate elements in structured meshes This can be done by selecting Mesh gt Structured gt Lines gt Concentrate elements First we must select the lines that need to be assigned an element concentration weight The value of this weight can be either positive or negative depending on whether the user wants to concentrate elements at the beginning or end of the lines Next a vector appears which defines the start and end of the line and which helps the user
91. module will calculate values for each element of the mesh and store the values in a file in such a way as they can be read by GiD Post process 10 1 Introduction Our aim is to solve a problem that involves calculating the center of gravity center of mass of a 2D object To do this we need to develop a calculating module that can interact with GiD The problem calculate the center of mass The center of mass Xcm Ycm of a two dimensional body is defined as where p x y is the density of the material at point x y and S is the surface of the body mi are concentrated masses applied on the point Xi yi To solve the problem numerically the integrals will be transformed into sums Introduction 160 Each of the N elements is treated as concentrated weight whose mass is defined as the product of the surface density and the area of the element 10 1 1 Interaction of GiD with the calculating module GiD Preprocess makes a discretization of the object under study and generates a mesh of elements each one of which is assigned a material and some conditions This preprocessing information in GiD mesh materials and conditions enables the calculating module to generate results For the present example the calculating module will find the distance of each element relative to the center of mass of the object Finally the results generated by the calculating module will be read and visualized in GiD Post process Preaprocess Postp
92. n 0 0 Bus 0 0 opac s E OK Cancel 2 5 4 Send entities to a layer User can send entities to a specific layer As an example we are going to send to the layer Auxiliar a part of the model 1 Select the layer Auxiliar in the Layers window 2 Select the option Send to from the right mouse button or click icon 3 Select Volumes and select the volume shown in red in the following figure Send entities to a layer 13 4 Then press Escape to exit the selection mode 5 Set the render mode to Flat The color of selected volume has changed to the one of the layer Auxiliar as shown in the following figure Send entities to a layer 14 2 5 5 Switch On Off By clicking on the user can switch on and off the corresponding layer This is very useful in order to visualize icon which is next to each Layer inside the Layers and groups window just some specific parts of the model 2 5 6 Freeze a layer At the right side of the bulb user can set an icon which is a lock If the lock is closed the layer is frozen If a layer is frozen GiD won t apply anything to the entities of that layer For instance if user select some entities to be deleted if they are into a frozen layer they won t be erased 2 5 7 Transparency Next to the lock icon of each layer is the transparency icon By clicking there the user can set a layer to be transparent or not The following figure shows the model with the
93. n and Surfaces Make a translation of 110 units Enter two points that define a vector for this translation for example 0 0 0 and 0 O 110 6 To create the volume defined by the translation select Do Extrude Volumes in the Creating the volume of the prism 60 Copy window 7 Click Select and select the surface of the octagon Press ESC The result is shown in next figure Figure 25 Creation of the volume of the prism 8 Choose the option Render gt Flat from the mouse menu to visualize a more realistic version of the model Then return to the normal visualization using Render gt Normal Figure 26 Visualization of the prism with the option RenderFlat Lg NOTE The Color option in the Layers window lets you define the color and the opacity of the selected layer This color is then used in the rendering of elements in that layer 4 4 3 Creating the volume of the wheel 1 Visualize the profile layer and activate it The volume of the wheel will be created in this layer Set off the prism layer in order to make the selection of the entities easier 2 In the Copy window choose Translation and Surfaces A translation of 10 units will be made To do this enter two points that define a vector for this translation for example 0 0 0 and 0 O 10 3 Choose the option Do Extrude Volumes from the Copy window The volume that is defined by the translation will be created 4 Make sure that the Maintain La
94. ndow appears in which the maximum element size should be entered Leave the default value unaltered and click OK 7 Once the mesh has been generated select Label gt All in gt Points The result is shown in Figure 16 Now there are not only nodes at the vertices but also at the midpoints of the edges of the elements Generating the mesh using quadratic elements 113 2736 2503 2807 2663 2877 2582 2800 2643 2509 2712 2440 2601 2644 2511 2878 2583 2806 2662 2734 2828 Figure 16 Each number identifies a node There is a node at each element vertex and at the midpoint of each edge 8 Select Mesh gt Quadratic type gt Quadratic9 9 Select Mesh gt Generate mesh 10 A window opens asking whether the previous mesh should be eliminated Click Yes 11 Another window appears in which the maximum element size should be entered Leave the default value unaltered and click OK 12 Select Label gt All in gt Points see Figure 17 13 Notice that the four sided elements quadrilaterals also have a node in the center in addition to the nodes at the vertices and midpoints of the edges Similarly hexahedra also have a node at their center point i eT 3897 woe ae 4789 Mas ae i eed A076 Pa 4603 ABA ia rae 4455 a2 PA p 4255 o m A55 A086 an pe ai O A 4199 mai 8970 we PS gon 4315 a 4085 a _ ea wee a AA56 Mens is AGO 4344 A i 4638 Figure 17 Each number identifies a node The
95. ndow is opened Select a new color 8 Press Apply and then Close Select and display style 21 Double click here to integrate the window Volumes Surfaces Cuts E alphabetic order YO St Tr Int Ew b Elements 5 268 tetrahedrons V Aux 2 0 i 2 919 tetrahedrons O 0 BS G rnme ZASI TEE Global settings Preprocess information Style J BodyBound Show conditions None Render Normal a Draw model None Model render Normal Culling No Let s play with some visualization options 9 Select Body Lines in the Style option at the bottom of the window You can also do it clicking on bg in the St column or the same icon in the main window 10 Click on the icon of Aux layer in order to switch it off It s possible to draw preprocessing information for example the geometry 11 In Draw Model option select Geometry Now our model should look like this Select and display style 22 l V a Hf N D P ti i V f A i LN i a 1 s ley 1g NOTE The View style window can be integrated inside GiD interface just double click on the upper bar of the window To tear it off again double click the upper bar again NOTE Mesh styles can also be changed clicking on the icon Pi placed in the left icon bar This style affects all sets of the model 23 3 INITIATION TO PREPROCESSING With
96. ng the post res file The output data results are stored in this file The format of the post res file is explaned in the GiD help see section Posprocess data files gt Postprocess results format writing post res strcpy filename projname strcat filename post res fo fopen filename w tprintf ip Gil Post Results pile 1 0 fprintf fp Result MC DISTANCE LOAD ANALYSIS 1 Scalar OnNodes EFprintt fp ComponentNames MC DISTANCE fprintf fp Values for 1nod 1 inod lt Nnod inod distance or each node to the center of masses v sqri x CG x inod x CG x inod y CG y inod y CG y ined Porincr ip sd alt manod y j tporintf ip End values fclose fp In this example only a scalar result with a single time step is written in the res file This is the full source code of this program include lt stdio h gt Fone ide lt stdlib h gt include lt malloc h gt Fincluae lt maclh h gt The main program define MAXMAT 1000 define MAXCND 1000 char projname 1024 int i ielem inod icnd double x y inc N imac int nodc MAXCND double rho MAXMAT wval MAXCND int Nelem Nnod Nmat Ncnd double x CG y CG yord input void void calculate void void output void void Main int argc char argv 4 strcepy projname argv 1 input y calculate ou utpurt y void input
97. nter size of elements to be generated 10 v _ Get meshing parameters from model Figure 28 Choosing elements size 3 A window appears showing how the meshing is progressing Once the process is finished it show information about the mesh that has been generated Click View mesh to visualize the resulting mesh Mesh generated Fi Num of Tetrahedra elements 3448 T Num of nodes 1300 Num nodes Meshing evolution Figure 30 The mesh generated 012345678910 Time seconds i L Figure 29 Mesh generated information 4 Use the Mesh gt View mesh boundary option to see only the contour of the volumes meshed without the interiors This visualization mode may be combined with the various rendering methods 5 A window appears asking if we want to maintain this visualization mode Click No To exit the mesh boundary visualization mode press ESC Generating a coarse mesh hy a ar hee 1 ah La att AL 5 a wae ce ug a Tt F at igh he a 4 a im mut T e a Lao rh aia xe ay By cai fee fl nk et a E aey h a Poh ee oh ak oi i he Ey i he t i rit cS rg ll fo 4 Taag pra ae d Pe raw VET TI E AT ere i a Aai ak ee E Haa LTA s A fa Le al Pe
98. ntour This option is also available in the toolbar ni Select all the surfaces and press ESC twice GiD automatically generates the volume of the cube The volume viewed on the screen is represented by a cube with an interior color of sky blue Before proceeding with the mesh generation of the volume we should eliminate the information of the structured mesh created previously for the surface Do this by selecting Mesh gt Reset mesh data and the following dialog box will appear on the screen Creation and meshing of a volume 40 sure you want to reset all meshing information In which the user is asked to confirm the erasure of the mesh information qa NOTE Another valid option would be to assign a size of O to all entities This would eliminate all the previous size information as well as the information for the mesh and the default options would become active Next generate the mesh of the volume by choosing Mesh gt Generate mesh Another Auxiliary Window appears into which the size of the volumetric element must be entered In this example the value is 1 py p eepe een aa ia j a Mesh generated Mum of Tetrahedra elements 9948 O Num of nodes 2023 Meshing evolution 4 5 6 Time seconds Creation and meshing of a volume 41 e ee ee 7h tho Ae Fel oe ee T aa EE a I a j TAERA y DA ZS k m k z dare S ami IA TANE tte TN a rh
99. o be found in the GiD Toolbar Select Render gt Normal in the mouse menu to see the labels 2 Select Mesh gt Element type gt Circle Select surface number 24 and press ESC 3 Select Mesh gt Generate mesh 4 A window comes up asking whether the previous mesh should be eliminated Click Yes 5 Another window appears in which to enter the maximum element size Leave the default value unaltered and click OK The result is a mesh as illustrated in Figure 4 Generating the mesh using circles and spheres 101 Figure 4 Render Flat Generating a mesh on a volume using points Figure 4 Render Normal Generating a mesh on a volume using points 7 2 3 Generating the mesh using points 1 Select Mesh gt Element type gt Only points Select volume number 1 and press ESC 2 Select Mesh gt Generate mesh 3 A window comes up asking whether the previous mesh should be eliminated Click Yes 4 Another window appears in which to enter the maximum element size Leave the default value unaltered and click OK The result is a mesh as illustrated in Figure 5 Generating the mesh using points 102 NS N a N Po o Ji oe aie ee ma eee va E L rF i may ae fale EA E a AAN Aiea Figure 5 Generating a mesh on a volume using points 5 Now volume number 1 is meshed using only the generated nodes 1
100. o indicate that the process of creating lines is finished At B Figure 1 Profile of one of the disks around the pipe 3 From the Copy window choose Lines and Translation A translation defined by points A 0 11 as first point and B 15 11 as second point will be made In the Multiple copies option enter 8 the number of copies to be added to the original Be sure than the Collapse option is set and then Select the lines that have just been drawn and press ESC Figure 2 The profile of the disks using Multiple copies 4 Create a line using Geometry gt Create gt Straight line Use the contextual option Join or press lt Ctrl a gt and select the last point on the profile at the right part of the profile Now choose the option No join Ctrl a and enter new point 160 11 in the command line Press ESC twice to finish the process of creating lines 5 Again choose the Line option and enter the new points 0 9 and 160 9 Press ESC twice to conclude the process of creating lines 5 2 2 Creating the surfaces by revolution Creating the surfaces by revolution 71 Rotation of the profile will be carried out in two rotations of 180 degrees each 1 From the Copy window select Lines and Rotation Enter an angle of 180 degrees and from the Do extrude menu select Surfaces The axis of rotation is that defined by the line that goes from point 0 0 to point 200 0 Enter these two points as the First Point and Second
101. ocess Interaction of GiD with the calculating module 162 mat Praprocess GiD cng E 7 i project name dat Fa aJl Results file Postprocess mesh file project name po BT res project nar i p st maeti Postprocess GiD Diagram depicting the files system 10 2 Implementation Creating the Subdirectory for the Problem Type Create the subdirectory cmas2d gid This subdirectory has a gid extension and will contain all the configuration files and calculating module files prb mat cnd bas bat exe 1 NOTE If you want the problem type to appear in the GiD Data gt Problem type menu create the subdirectory within problemtypes located in the GiD installation folder for example C GiD Problemtypes cmas2d gid 10 2 1 Creating the Materials File Create the materials file cmas2d mat This file stores the physical properties of the material under study for the problem type In this case defining the density will be enough Creating the Materials File 163 Enter the materials in the cmas2d mat file using the following format MATERIAL Name of the material without spaces QUESTION Property of the material For this example we are interested in the density of the material VALUE Value of the property HELP A help text optional field END MATERIAL In GiD the information in cmas2d mat file is managed in the materials window located in Data gt Materials MATER
102. of the iso surface can also be changed as with the volume and surface meshes In order to see the inner zones we will set the transpacency on the iso surfaces 4 Select Options gt Iso Surfaces gt Transparency gt Transparent 5 Move the model to see the inner zones 6 Select Options gt Iso Surfaces gt Transparency gt Opaque 1 5436 1 2863 1 0291 0 77181 0 51454 0 25 27 Other interesting options are Iso surfaces 120 Options gt Iso surfaces gt Convert to cuts which consolidates the isosurface as mesh which can be exported to a file Options gt Iso surfaces gt Color Mode allows to draw the iso surfaces with a single colour Monochrome according to the results used to create the iso surface Result color or using the color map of the visualized contour fill result Contour fill color Options gt Iso surfaces gt Show isolines this option allows the user to switch isolines of surafaces on or off Options gt Iso surfaces gt Draw always if this option is selected the iso surfaces are always drawn even though all the meshes are switched off 8 3 2 Animate Menu Window gt Animate This window allows the user to animate the current visualized results If only one step is present then the Static analysis animation profile button is enabled so that a custom animation profile can be step to animate that one step Animate Eal Options Results View Automatic Limits Deformation E Endless
103. on and meshing of a line 26 the user qd NOTE The size of an element with two nodes is the length of the element For surfaces or volumes the size is the mean length of the edge of the element In this example the size of the element is defined in concordance with the length of the line chosen for this case as size 1 Click OK Enter size of elernents to be generated a CS L Get meshing parameters from model Once the mesh has been generated a window with the mesh information appears Click View mesh Wipe ee ee aE TROUPES TT PPE S Pry Mesh generated Num of Linear elernents 10 Num of nodes 11 Meshing evolution 4 5 6 Time seconds Automatically GiD generates a mesh for the line The finite element mesh is presented on the screen in a grey color Creation and meshing of a line 27 The mesh is formed by ten linear elements of two nodes To see the numbering of the nodes and mesh elements select from the Mouse Menu Label gt All and the numbering for the 10 elements and 11 nodes will be shown as below 1i 1l 10 Fa 4 R ft 4 fi h z i 4 Once the mesh has been generated the project should be saved To save the example select from the Top Menu Files gt Save The program automatically saves the file if it already has a name If it is the first time the file has been saved the user is asked to assign a name For this an Auxiliary Window will appear which permits the user to browse the
104. one shown in Figure 9 is obtained when the option Utilities gt Preferences gt Meshing gt Symmetrical structured gt tetrahedra is set If this option is not set the mesh presented in Figure 10 is produced with fewer nodes than if using the previous option also it is not topologically symmetrical Generating structured meshes volumes 107 Figure 10 Structured volume mesh of tetrahedra with the option Symmetrical structured tetrahedra not set 7 2 7 Generating semi structured meshes volumes 1 To mesh volumes with a semi structured mesh select the option Mesh gt SemiStructured gt Volumes 2 A window appears in which to enter the number of divisions for the direction in which it is structured the prismatic one Enter 8 and click Assign 3 Select volume 3 and press ESC As volume 3 is prismatic in one direction only i e parallel to Y axis GiD will automatically detect this fact and will select it to be the direction in which the semi structured volume mesh is structured 4 Another window appears in which to enter the number of divisions in the direction of the structure In this case we do not want to select any more volumes so click Close 5 Select Mesh gt Generate mesh 6 A window appears asking whether the previous mesh should be eliminated Click Yes 7 Another window appears in which to enter the maximum element size Leave the default value unaltered and click OK The result is the mesh shown in Figure 11
105. onformal mesh 158 Mesh generated Num of Triangle elements 4196 Num of nodes 4022 Num nodes Meshing evolution Memory KB 10000 9000 8000 7000 6000 4000 a 10 12 14 Time seconds Information about the generated mesh after uncollapse 4 Visualize the result using Mesh gt View mesh boundary HigherEntities 2 Interior 1 Boundary edges higer entities after uncollapse 159 10 DEFINING A PROBLEM TYPE This tutorial takes you through the steps involved in defining a problem type using GiD A problem type is a set of files configured by a solver developer so that the program can prepare data to be analyzed A simple example has been chosen which takes us through all the associated configuration files while using few lines of code Particular emphasis is given to the calculation of the centers of mass for two dimensional surfaces a simple formulation both conceptually and numerically The tutorial is composed of the following steps Starting the problemtype Creating the materials definition file Creating the general configurations file Creating the conditions definition file Creating the data format file Creating the calculating program file and the execution files Executing the calculating module and visualizing the results using GiD By the end of the example you should be able to create a calculating module that will interpret the mesh generated in GiD Preprocess The
106. orfile 327 1 err A comment line such as rem ErrorFile file name err means that the indicated file will contain the errors if any If the err file is present at the end of the execution a window comes up showing the error The absence of the err file indicates that the calculation is considered satisfactory GiD automatically deletes the err files before initiating a calculation to avoid confusion del 2 3 31 lo0g del 2 1 post res This deletes results files from any previous calculations to avoid confusion 3 cmas2d exe 2 51 This executing the cmas2d exe and provide the dat as input file file Using the problemtype with an example 174 10 3 Using the problemtype with an example In order to understand the way the calculating module works simple problems with limited practical use have been chosen Although these problems do not exemplify the full potential of the GiD program the user may intuit their answers and therefore compare the predicted results with those obtained in the simulations 1 Create a surface for example from the menu Geometry gt Create gt Object gt Polygon 2 Create a polygon with 5 sides centered in the 0 0 0 and located in the XY plane normal 0 0 1 and whit radius 1 0 Surface used for this example 3 Load the problemtype menu Data gt Problem type gt cmas2d 4 Choose Data gt Materials 5 The materials window is opened From the Materials menu in this window cho
107. ose the option Air Materials Ka Density 1 01 Assign Draw Unassign Materials window 6 Click Assign gt Surfaces and select the surface Press ESC when this step is finished 7 Choose the Mesh gt Generate option 8 A window appears in which to enter the maximum element size for the mesh to be generated Accept the default value and click OK The mesh shown will be obtained Using the problemtype with an example 175 The mesh of the object 9 Now the calculation may be initiated but first the model must be saved Files gt Save use example_cmas2d as name for the model 10 Choose the Calculate option from the Calculate menu to start the calculation module 11 Wait until a box appears indicating the calculation has finished Process example_cmas2d Started at Mon Apr 23 15 30 33 has finished Process information window 12 Select the option Files gt Postprocess 13 Select Window gt View results 14 A window appears from which to visualize the results By default when changing to postprocesses mode no results is visualized 15 From the View combo box in the View Results window choose the Contour Fill option A set of available results only one for this case are displayed Using the problemtype with an example 176 View results Main Mesh Reference mesh View No Result o Step View Contour Fill o Step Analysis LOAD ANALYSIS l Analysis LOAD ANALYSIS l lt No r
108. ough the Results menu opening the View Results window or through the results view icon bar Menu View Results Window gt View Results Viewing the results 118 eee Ere TOrMATION View results Main Mesh Reference mesh View Contour Fill Step Analysis RANSOL Velocity m s Vorticity 1 5 factor Results view icon bar Files View Utilities Do cuts T L ETERNITA a re ama een Pe D ETIE DPO aP B D _ ne Ran Iso surfaces 119 8 3 1 Iso surfaces Menu View results gt Iso Surfaces With this result visualization a surface or line is drawn passing through all the points which have the same result s value inside a volume mesh or surface mesh To create isosurfaces there are several options 1 Select View results gt Iso Surfaces gt Automatic Width gt Velocity m s gt V throught the menu bar or clicking on Son the results view icon bar After choosing the result you are asked for a width This width is used to create as many isosurfaces as are needed between the Minimum and Maximum defined values these are included 2 enter the value 0 25727 to get the picture below 3 Select View gt Render gt Smooth in order to get a better view Several configuration options can be set via the Options menu Menu Options gt Iso surfaces Using Options gt Iso surfaces gt Display Style the style
109. r Set pipe2 inner as the layer to use and set off the layers pipe1 2 Choose Geometry gt Create gt Point and enter points 20 9 and 20 11 Press ESC to conclude the creation of points 3 Change the layer of the second point to pipe2 outer 4 From the Copy window select Points and Rotation Enter an angle of 180 degrees and from the Do extrude menu select Lines Since the rotation can be done on the xy plane choose Two Dimensions The center of rotation is the coordinates 20 O 0 and set Multiple copies to 2 5 Click Select and select the two points just created Creating the other pipe section 77 6 Create a surface choose Geometry gt Create gt NURBS Surface gt By contour and select the four lines Press ESC twice 7 From the Copy window select Surfaces and Translation In First Point and Second Point enter the points defining the translation vector Since this pipe section must also measure 40 length units the vector is defined by points 0 0 0 and 0 O 40 8 From the Do extrude menu select the Volumes option and set Multiple copies to 1 9 Click Select to select the surface and press ESC to conclude the selection Figure 13 A rendering of the two overlapping pipes 5 3 3 Creating the lines of intersection 1 Set off the layers outer to facilitate the selection 2 Choose Geometry gt Edit gt Intersection gt Surfaces 3 Select the three inner surfaces of the pipes th
110. raph in wake 1 Step 108 Graphs 137 The graph size is readapted We can will change several style options of a graph 18 Double click in any point of the graph and we will access to the Options tab 19 Choose Line in the Style option 20 Set to red the Color option You can do it writing ff0000 or selecting the red clicking on the right color window 21 Set to 4 0 the Line width 22 Click on Apply button Graph sets options can be managed selecting the set in the tree 23 Select Velocity branch The options will change 24 For instance mark Logarithmic scale option in X axis 25 Click on Apply button Graphs Window Velocity bi kela Plot graph Create Options Aveo M e i Line Graph in wake 1 Step Legend location Upper right Et pa phset 1 Background Transparent Pressure Pa evolution at Soe peer ie A axis Y axis Logarithmic scale Logarithmic scale Minimum 0 Minimum 0 252798 Maximum 47 Maximum 1 22051 Divisions 10 Divisions a Label Label w Unit Unit Coordinates type Cartesian Polar axis Values as angle Use Use Degrees as angle unit Show axes in 0 0 point Show radial marks Continous Style Outline on model Grids El We can export the graph information in order to open it later with GiD 26 Select Files gt Export gt Graph gt All You are asked for the location where to save the grf file 27 Choose the location Now you
111. re is a node at each vertex at the midpoint of each edge and in the center of quadrilaterals and hexahedra POSTPROCESSING 114 115 8 POSTPROCESSING The objective of this tutorial is to do a postprocess analysis of an already calculated fluid Simulations no preprocess option is used Not only the model is already meshed and the constraints are assigned but also the results have been calculated For more information about the preprocess part of GiD please check the preprocess tutorials In this tutorial the model Cylinder bin has been used The problem type used to do this Simulations is Tdyn particularly the Ransol model Tdyn is a fluid dynamic CFD simulation environment based on the stabilized Finite Element Method Steps followed in this tutorial Loading the model Changing mesh styles Visualization of results Creating images 8 1 Loading the model There are two ways to load the results simulation information into GiD If the model has been calculated inside GiD the results are also inside the GiD model then just load the GiD project and change to postprocess mode This can be achieved clicking on this icon Loading the model 116 D Or selecting the Files gt Postprocess menu entry If only a mesh and results file s are present then GiD should be started and switched to postprocess mode D before loading the file s For this tutorial we will use the file called Cylinder bin th
112. red square drawn inside the original four lines Once the surface has been created the mesh can be created in the same way as was done for the line From the Top Menu select Mesh gt Generate mesh A window appears asking if the previous mesh should be elliminated Click Yes Dialog window The old mesh will be erased Continue Another window appears which asks for the maximum size of the element in this example defined as 1 Creation and meshing of a surface 30 We can see that the lines containing elements of two nodes have not been meshed Rather the mesh generated over the surface consists of planes of three nodded triangular elements Ly NOTE GiD meshes by default the entity of highest order with which it is working GiD allows the user to concentrate elements in specified geometry zones Next a brief example will be presented in which the elements are concentrated in the top right corner of the square This operation is realized by assigning a smaller element size to the point in this zone than for the rest of the mesh Select the following sequence Mesh gt Unstructured gt Assign sizes on points The following dialog box appears in which the user can define the size eB BANY WAVAVAVAVAN KOK AALAN I Seal KNOX Creation and meshing of a surface 32 point Various possibilities exist for controlling the evolution of the element size which will be presented later in the manual To gener
113. rface Select the option Geometry gt Delete gt Surfaces and then select Creating a hole in the mechanical part 57 the surface of the octagon Press ESC to finish Figure 17 Regular 8 sided polygon 4 3 1 Creating a hole in the surface of the mechanical part 1 Choose the option Geometry gt Edit gt Hole NURBS surface 2 Select the surface in which to make the hole Figure 18 3 Select the lines that define the hole Figure 19 and press ESC Figure 18 The selected surface in which to Figure 19 The selected lines that define the create the hole hole 4 Again press ESC to exit this function Creating a hole in the surface of the mechanical part 58 CA Figure 20 The model part with the hole in it 4 4 Creating volumes from surfaces The mechanical part to be constructed is composed of two volumes the volume of the wheel defined by the profile and the volume of the axle which is a prism with an octagonal base that fits into the hole in the wheel Creating this prism will be the first step of this stage It will be created in a new layer that we will name prism 4 4 1 Creating the prism layer and translating the octagon to this layer 1 In the Layers window create a new layer named prism 2 Select the prism layer and double click it to choose as the activated layer 3 Right click on prism layer and select Send To gt Lines Select the lines that define the octagon Press ESC to conclude the sel
114. rials format 4i 13 5e set var PROP1 real Operation MatProp Density real MatNum PROP1 end Point conditions Creating the Data Format File Template file Set Cond Point Weight nodes set var NFIX int CondNumeEntities int Concentrated Weights NFIX Potentials Prescrits Node Tipus Valor Etiqueta Set Cond Point Weight nodes loop nodes OnlyInCond NodesNum cond 1 end 10 2 5 Creating the Execution file of the Calculating Module 171 Create the file cmas2d c This file contains the code for the execution program of the calculating module This execution program reads the problem data provided by GiD calculates the coordinates of the center of mass of the object and the distance between each element and this point These results are saved in a text file with the extension post res Compile and link the cmas2d c file in order to obtain the executable cmas2d exe file The calculating module cmas2d exe reads and generates the files described below Creating the Execution file of the Calculating Module 172 READS the dat file coordinates gt x y connectivities H EET densities rha aE conditions nodc condition value wal void input CREATES the err file This fle is created only if an error oocurs put of memory element with no material project_nanme err CALCULATION of th void calculate E CENTER of MASSESS CREATES the log
115. rmation file strcpy filename projname strcat filename log fplog fopen filename w fprintf fplog CMAS2D routine to calculate the mass center fprintf fplog project s projname Eprinti iplog mass center slit 41I T X CG y CG fclose fplog writing post res strcpy filename projname strcat filename post res fp fopen filename w tprinti tp Gib Post Results File 1 0 7 fprintf fp Result MC DISTANCE LOAD ANALYSIS 1 Scalar OnNodes fprintf fp ComponentNames MC DISTANCE fprintf ip Values for 1n0od 1 inod lt Nnod inod distance or each node to the center of masses V SOrL x CG xlinod x Ce6 x inod ly CG y i1nod y Ce y ined 7 forinti ip d cli inod vi forinti tip End values fclose fp free x free y free N The main program 188 free imat void jumpline FILE filep char buffer 1024 fgets buffer 1024 filep
116. rocess B SOLVER INPUT OUTPUT FILE FILE Diagram of the workflow GiD must adapt these data to deal with them Materials boundary and or load conditions and general problem data must be defined GiD configuration is accomplished through text formatted files The following files are required prb configuration of the general parameter not associated to entities Interaction of GiD with the calculating module 161 mat configuration of materials and their properties cnd configuration of the conditions imposed on the calculation bas template file the file for configuring the format of the interchange file that mediates between GiD data and the calculating module The file for interchanging the data exported by GiD has the extension dat This file stores the geometric and physical data of the problem bat the file that can be executed called from GiD This file initiates the calculating module The calculating module in this example cmas2d exe solves the equations in the problem and saves the results in the results file This module may be programmed in the language of your choice C in used in this example GiD Post process reads the following files generated by the calculating module project_name post res results file Each element of the mesh corresponds to a value project_name post msh file containing the post process mesh If this file does not exist GiD uses the preprocess mesh also for postpr
117. same general mesh size 10 The resulting mesh has a high concentration of elements in curved areas Now our approximation is significantly improved see Figure 10 wal 3 ee tt wea a ne eras beo rena ii SEE eE A APA tM eee TH SO Spee ere a P Yaw iar Sa el oa i Eo Say m ong res aT i V M A A Z i z Ae p ESS R T A S A et A a a sr 5 Phill et a ae a aes pase TES Ny ful oe es IN aes eeepc LAE Sets SQ Tie a ANS wis Pa at eee a a es oe a y Ki PEE A ama a ee Zana SST SS iy fyi AAA ara ih A fa i Vy Mae Fag a Nees OS S Sa INE al rE eae EnaA i nk I T i gaT A okt ha i eee OO Nae AAA Ne l eee eS WS re NR Mi SESS NAY ve Pasig A ee awa i ne Reece Te ae Sf les rary 3 So a We Me eee eS OL x S i IPA NO interes Tu etter en i MAM PS i UNDG Ere E i T Aiae REA AY Figure 10 Mesh using sizes assignment by chordal error Here there is a greater concentration of elements in the curved zones 6 3 Rj ump mesher The RJump mesher is a surface mesher that meshes patches of surfaces in 3D space and is able to skip the inner lines of these patches when meshing By default the RJump mesher skips the contact lines between surfaces and points between lines that are tangent enough By selecting Mesh gt Draw gt Skip entities Rjump the entities that the actual mesh is going to skip and the ones that it is not going
118. screen use the Zoom Frame option which is located in the GiD toolbar and in Zoom in the mouse menu Figure 2 Creating a straight line 1 NOTE The Undo option located in Utilities gt Undo enables you to undo the most recent operations When this option is selected a window appears in which all the operations to be undone can be selected l The GiD Toolbar is a window containing the icons for the most frequently executed operations For information on a particular tool click on the corresponding icon with the right mouse button 2 The coordinates of a point may be entered on the command line not enclosed in parentheses either with a space or a comma between them If the Z coordinate is not entered it is considered O by default After entering the numbers press Return Another option for entering a point is using the Coordinates Window found in Utilities gt Tools gt Coordinates Window Pressing the ESC key is equivalent to pressing the center mouse button 4 2 2 Dividing the auxiliary line near coordinates 40 0 1 Choose Geometry gt Edit gt Divide gt Lines gt Near point This option will divide the line at the point element on the line closest to the coordinates entered 2 Enter the coordinates of the point that will divide the line In this example the coordinates are 40 0 On dividing the line a new point entity has been created 3 Select the line that is to be divided by clicking on it 4 Press
119. sented a little bit differently from surface meshes although in both cases triangles are shown If the triangles you see are the boundary of a volume mesh they are shown with black edges that are thicker than surface meshes triangles If the triangles form a boundary volume mesh and at the same time a triangle surface mesh this can be obtained if surfaces are selected with the option Mesh gt Mesh criteria gt Mesh gt Surfaces the wider edges are colored with the color of the surface layer Examples of these different kinds of render are shown in Figure 3 LW gt A CR Tar DRS Ms eee ait as ZN YNNSB Rs FTO SAADKY PRET N v 22 L AS NN TA avi Ts pat aD IZ GAIN aise ae ay ee i ee po ea Th FS LG l 2 Figure 2 Generating the mesh by default Generating the mesh by default 100 Figure 3 Different render styles a surface mesh b volume mesh c surface mesh and volume mesh together surface layer is red and volume layer is blue 7 2 2 Generating the mesh using circles and spheres 1 Select Mesh gt Element type gt Sphere Select volume number 1 and press ESC To see entity numbers select Label from the mouse menu or from the View menu If you wish the geometrical entity labels to be displayed the view mode needs to be changed to Geometry using View gt Mode gt Geometry this option may als
120. sh using circles Generating a volume mesh using points Generating a mesh using quadrilaterals Generating a structured mesh on surfaces and volumes Generating a semi structured volume mesh Generating a mesh using quadratic elements 7 1 Introduction In order to carry out this example start from the project ToMesh3 gid This project contains a geometry that will be meshed using different types of elements 7 1 1 Reading the initial project 1 In the Files menu select Read Select the project ToMesh3 gid and click Open 2 The geometry appears on the screen It is a set of surfaces and three volumes Select Render gt Flat from the mouse menu or from the View menu In Figure 1 shows the Reading the initial project 98 geometrical model loaded 3 Rotate and make several changes in the perspective so as to get a good idea of the geometry involved Figure 1 Contents of the project ToMesh3 gid Finally return to the normal visualization Render gt Normal This mode is more user friendly 7 2 Types of mesh Using GiD the mesh may be generated in different ways depending on the needs of each project The two basic types of meshes are the structured mesh and the unstructured mesh For volumes only there is one additional type the semi structured mesh For all these types of mesh a variety of elements may be used linear ones triangles quadrilaterals circles tetrahedra hexahedra prisms spheres or points
121. sions in the structured direction prismatic Enter 6 15 Select volume 1 and press ESC 16 Another window appears click Close 17 Select Mesh gt SemiStructured gt Set gt Structured direction 18 Select one line parallel to the X axis of volume number 1 for example line number 11 and press ESC 19 Select Mesh gt Unstructured gt Assign entities gt Surfaces 20 Select surfaces 1 and 6 and press ESC 21 Select Mesh gt Generate mesh 22 A window opens asking whether the previous mesh should be eliminated Click Yes 23 Another window appears in which to enter the maximum element size Leave the default value unaltered and click OK 7 2 8 Concentrating elements and assigning sizes 1 Select Mesh gt Structured gt Lines gt Concentrate elements Concentrating elements and assigning sizes 110 2 Select some structured lines for example line 43 Press ESC 3 A window comes up in which to enter two values for the concentration of elements Positive values concentrate the elements and negative values spread them Enter 0 5 as Start Weight and 0 5 as End Weight Click Ok and press ESC 4 Select Mesh gt Generate mesh 5 A window opens asking whether the previous mesh should be eliminated Click Yes 6 Another window appears in which to enter the maximum element size Leave the default value unaltered The result is the mesh shown in Figure 13 Figure 13 Concentration of elements on line 43
122. t gt Intersection gt Lines in order to make another intersection between the lower circle and the line segment between point 40 0 and point 55 0 see next figure Intersecting lines 52 Figure 11 Intersecting lines 9 Then continue selecting to make an intersection between the upper circle and the farthest segment of the line that was rotated 36 degrees see next figure Figure 12 Intersecting lines Creating an arc tangential to two lines 53 4 2 8 Creating an arc tangential to two lines 1 Choose Geometry gt Create gt Arc gt Fillet curves 2 Enter a radius of 1 35 in the command line 3 Now select the two line segments shown in next figure Then press ESC to indicate that the process of creating the arcs is finished Figure 13 The line segments to be selected 4 2 9 Translating the definitive lines to the profile layer The auxiliary lines will be eliminated and the profile layer will contain only the definitive lines 1 Select the profile layer in the Layers window 2 We will move the lines defining the profile to the profile layer Click on the icon 2 Send To and select Lines Be sure that Also lower entities is chequed to send to this layer also the points of the lines 3 Select only the lines that form the profile see next figure 4 To conclude the selection process press the ESC key or click Finish in the Layers window Translating the definitive lines to the profile l
123. t long Wait until the red circle turns to green 10 Close the Animate window Now we will visualize another result but before we will clear all the results 11 Select View results gt No results through the menu bar or using the icon y 8 3 3 Result surface Another result visualization of interest is this one Result surface 122 Pressure Pa 0 5624 0 41149 0 26058 0 10967 0 041235 0 19214 0 44305 0 49396 0 64487 0 79578 To get this visualization follow these steps 1 Switch off all the sets except S interior cil To do this Select Window gt View style in the menu bar Select all the sets except S interior cil pressing Ctrl while selecting with mouse Click on the bulb light icon on the I O column or click on the icon 2 Through the View style window change the Style to Body Bound 3 Select View results gt Result surface gt Pressure Pa A surface will be drawn which results from moving the nodes along its smoothed normal according to the results value for this node 4 Enter 5 as factor in the bottom command line 5 Select Options gt Result surface gt Show elevations gt None 6 Select Options gt Result surface gt Show elevations gt Contour fill With this last option the surface is colored according to the pressure value Play with the other options as you will Result surface 123 7 Select View results gt No results through the menu bar or using the icon sta 8
124. t Mesh gt Unstructured gt Assign sizes on points A window appears in which to enter the element size around the points to be chosen Enter 0 1 and click Assign 4 Select the point indicated in Figure 4 point number 29 Press ESC to indicate that the selection of points is finished and Close the window 5 Generate the mesh again with the default general mesh size 6 The resulting mesh is depicted in Figure 11 A high concentration of elements around point number 29 can be appreciated Note that there are nodes on line number 43 because we have forced RJump not to skip this line See Figure 14 Force to mesh some entity 95 Hee y Sp 4 r 1 ee a 1 3 e a N Figure 14 Mesh using the RJump mesher assigning sizes by chordal error and forcing an entity to be meshed In this last example we have forced the mesher not to skip an entity but it may be interesting in some models to allow the mesher only to skip a few entities meshing almost all or them In this case a different surface mesher can be selected in the Preferences window One option is the RSurf mesher which meshes all the lines and point except the ones set explicitally to be skipped using the Mesh gt Mesh criteria gt Skip option Here because RJump is not selected no entity will be skipped automatically according to tangency with neighboring entities The next example shows how to work like this 7 Select Mesh gt Reset mesh da
125. t size can be entered Leave the default value unaltered and click OK 8 Choose the Calculate option from the Calculate menu thus executing the calculating module 9 Choose the Files gt Postprocess option 10 Visualize the new results Visualization of the distance from the mass center to each element for an object of heterogeneous material subject to point weight Now the condition is external point weight As anticipated the new center of mass is displaced toward the point under weight 10 4 Aditional information Aditional information 178 Ly NOTE In this example a code for the program will be developed in C Nevertheless any programming language may be used The code of the program that calculates the center of mass cmas2d c is as follows The cmas2d c file finclude lt stdio h gt tinclude lt stdlib h gt tincl de lt malloc bh gt rinclude lt math h gt define MAXMAT 1000 define MAXCND 1000 char projname 1024 int i ielem inod icnd double x y int N imat int nodc MAXCND double rho MAXMAT wval MAXCND int Nelem Nnod Nmat Ncnd Gouble x CG yY CG void inp t void void calculate void v id cutput void Declaration of variables and constants used in the program v id main i t argc Char targv 4 strcpy projname argv 1 input calculate Output 10 4 1 The main program The main program 179 The main program is
126. ta to reset all mesh sizes introduced previously A window opens advising that all the mesh information is going to be erased Press Ok 8 Set RSurf as the unstructured surface mesher in the Meshing branck of the Preferences window and click Apply 9 Select Mesh gt Mesh criteria gt Skip gt Lines and select lines 48 and 53 Press ESC 10 Generate the mesh with the default general mesh size 11 The result is a mesh similar to the first example obtained in chapter 2 see Figure 2 but the smaller elements highlighted in Figure 3 do not appear because lines 48 and 53 which were meshed before are now skipped when meshing see Figure 15 Force to mesh some entity 96 lt N AM DIY i E Ni fa EN a A lS Ve N A Lh ast ia aati of MV Kl W NAN ar A A is w a i i H A N n W pa etn tT ea f Vis ate y Fi im atl q A J yi iN yt f X y Ky N M y n Figure 15 Mesh using the RSurf mesher with some lines skipped 97 7 METHODS FOR MESH GENERATION The objective of this example is to mesh a model using the various options available in GiD for controlling the element type in structured semi structured and unstructured meshes It also presents how to concentrate elements and control the distribution of mesh sizes The six methods covered are Generating a mesh using tetrahedral Generating a volume mesh using spheres Generate a me
127. tabase we will first generate points 1 and 2 Next we will create points 1 and 2 To do this we will use an Auxiliary Window that will allow us to simply describe the points by entering coordinates It is accessed by the following sequence Utilities gt Tools gt Coordinates window Then from the Top Menu select Geometry gt Create gt Point In the coordinate window opened previously enter the coordinates of point 1 in the x y z entries and click Apply or press Enter on the keyboard Coordinates window C System Cartesian Local axes Global x 0 00000 y 0 00000 z 0 00000 Create new point Ask And create point 2 in the same way introducing its coordinates in the Coordinates window The last step in the creation of the points as well as any other command is to press Escape either via the Escape button on the keyboard or by pressing the central mouse button Select Close to close the Coordinates window In order to view everything that has been created to this point center the image on the Creation and meshing of a line 25 screen by choosing in the Mouse Menu Zoom gt Frame Now we will create the line that joins the two points Choose from the Top Menu Geometry gt Create gt Straight line Option in the Toolbar shown below can also be ae Next the origin point of the line must be defined In the Mouse Menu opened by clicking used the right mouse button select Contextual gt Join Ctrl a MM
128. ter Velocity for example We will create a new graph set 10 In the top part of the window click the Sicon A new graph set is created with default name graphset 1 When a new graph set is created becomes the current one We can see that there are no graphs on this new graph Set It s also possible to create graphs from the graph window 11 Go to Create tab and select Point evolution int View option 12 In Y Axis list double click Pressure Pa 13 Write 50 O O in the command line in order to specify the point 14 Press Escape to finish the graph We can manage graphs and graphs sets in the Options panel Depending if we are selecting a graph set or a graph in the tree we will see different options in the tab 15 Go to the Options panel select the Velocity m s evolution at 20 0 4 graph and delete it pressing the button with the red cross 16 A confirmation window appears Click Yes Graphs wiw ea Plot graph Create Options p Velocity Options g Velocity m s evolution at i Line Graph in wake 1 Step graphset 1 Pressure Pa evolution at Color 136 Visible DotLine Color as contour fill 1 0 Pattern factor 1 5 0 Point size P F Values 17 Please notice that the current graph set have been changed to Velocity Now the Plot graph panel will show only one graph Velocity telae Plot graph Create Options IVI Line G
129. th this example the user has been introduced to the basic tools for the creation of geometric entities and mesh generation 43 4 IMPLEMENTING A MECHANICAL PART 2D TOOLS BASIC 3D TOOLS AND MESHING IMPLEMENTING A MECHANICAL PART The objective of this case study is implementing a mechanical part in order to study it through meshing analysis The development of the model consists of the following steps Creating a profile of the part Generating a volume defined by the profile Generating the mesh for the part At the end of this case study you should be able to handle the 2D tools available in GiD as well as the options for generating meshes and visualizing the prototype A geometric representation is composed of four types of entities namely points lines surfaces and volumes A layer is a grouping of entities Defining layers in computer aided design allows us to work Defining the layers 44 collectively with all the entities in one layer The creation of a profile of the mechanical part in our case study will be carried out with the help of auxiliary lines Two layers will be defined in order to prevent these lines from appearing in the final drawing The lines that define the profile will be assigned to one of the layers called the profile layer while the auxiliary lines will be assigned to the other layer called the aux layer When the design of the part has been completed the entities in the aux layer w
130. ther to get a more comfortable view You can select several predefined color scales The default scale is standard which is a rainbow colour map starting from blue minimum through green and yellow to red maximum 1 Select Options gt Contour gt Color Scale gt Inverse Standard You can also define your own scale 2 Select Options gt Contour gt Color scale gt User defined or Options gt Contour gt Color Window In this window you can change the number of diferent colors used in the scale If you need more accuracy you can increase this number or decrease it for a higher contrast 3 Change the number of colors to 10 4 Click on Apply button 5 Click on Close button Pressure Pa 0 55696 0 41727 027759 0 13791 0 0017 787 0 14146 0 28115 0 42083 0 56052 0 7002 0 863988 Cuts In order to view the inner zone we will do several cuts along the model Contour fill cuts and limits 125 Pressure Pa 0 55696 O41f 27 02 7759 0 13791 0 0017 787 0 14146 0 28115 0 42083 0 56052 0 7002 0 83966 Menu Do cuts In order to make it easier first we will change the plane visualization 1 Please select View gt Rotate gt Plane XY Original through the menu bar XY Rotate gt Plane XY Original throught the mouse menu or clicking on ee and t Now you have a top view of the model 2 Select Do cuts gt Cut plane gt Succession through the menu bar or clicking on ae
131. this example the user is introduced to the basic tools for the creation of geometric entities and mesh generation 3 1 First steps Before presenting all the possibilities that GiD offers we will present a simple example that will introduce and familiarize the user with the GiD program The example will develop a finite element problem in one of its principal phases the preprocess and will include the consequent data and parameter description of the problem This example introduces creation manipulation and meshing of the geometrical entities used in GiD First we will create a line and the mesh corresponding to the line Next we will save the project and it will be described in the GiD data baseform Starting from this line we will create a square surface which will be meshed to obtain a surface mesh Finally we will use this surface to create a cubic volume from which a volume mesh can then be generated Creation and meshing of a line 24 3 2 Creation and meshing of a line We will begin the example creating a line by defining its origin and end points points 1 and 2 in the following figure whose coordinates are 0 0 0 and 10 0 0 respectively It is important to note that in creating and working with geometric entities GiD follows the following hierarchical order point line surface and volume 47 To begin working with the program open GiD and a new GiD project is created automatically From this new da
132. to skip are displayed in different colors In this chapter we will see the properties of this mesher RJump default options 92 6 3 1 RJump default options 1 Select Mesh gt Reset mesh data to reset all mesh sizes introduced previously 2 A window appears advising that all the mesh information is going to be erased Press Ok 3 Set the Default Values in the Meshing branch of the Preferences window 4 Select RJump as the unstructured mesher to use Preferences Meshing and click Apply 5 Generate the mesh with the default general mesh size 6 In the generated mesh the contact lines between surfaces that are tangent enough do not have nodes contact points between lines tangent enough are also skipped when meshing see Figure 11 ch A WO hl ARI Fo 5 a J w h 4 1 7 i F it ee Na r F k 7h bey Pass ml 1 Tes eie r mama aa ott J f my ea Li Fa i L Fa L 4 l Pi 4 _ L aot a n A i V Figure 11 Mesh using the RJump mesher Note that the smaller elements shown in Figure 3 do not appear in this mesh because of the properties this mesher Using the RJump mesher it is possible to assign sizes to different entities As an example select Mesh gt Unstructured gt Sizes by chordal error 7 In the window enter 0 05 as chordal error 8 Enter 10 as maximum meshing size and 0 1 as minimum meshing size 9 Press OK 10 Again generate t
133. w Min Max 8 3 8 Stream lines 8 3 9 Graphs 8 4 Creating images 9 CAD CLEANING OPERATIONS 9 1 Importing on GiD 9 1 1 Importing an IGES file 9 2 Correcting errors in the imported geometry 9 2 1 Meshing by default 9 2 2 Correcting surfaces 9 3 The conformal mesh and the non conformal mesh 9 3 1 Global collapse of the model 9 3 2 Correcting surfaces and creating a conformal mesh 9 3 3 Creating a non conformal mesh 10 DEFINING A PROBLEM TYPE 10 1 Introduction 10 1 1 Interaction of GiD with the calculating module 101 102 103 105 107 109 111 115 115 116 117 119 120 121 123 126 128 129 130 133 137 141 141 142 144 144 146 149 149 151 157 159 159 160 Table of Contents 10 2 Implementation 10 2 1 Creating the Materials File 10 2 2 Creating the General File 10 2 3 Creating the Conditions File 10 2 4 Creating the Data Format File Template file 10 2 5 Creating the Execution file of the Calculating Module 10 2 6 Creating the Execution File for the Problem Type 10 3 Using the problemtype with an example 10 3 1 Executing the calculation with a concentrated weight 10 4 Aditional information 10 4 1 The main program vi 162 162 164 164 165 171 172 174 176 177 178 1 INTRODUCTION This manual contains a collection of tutorials and practical information for learning the basics and advanced features of GiD covering full flow of GiD user from preprocessing to postprocessing going trough meshing anal
134. whole model Leave this default size unaltered and click OK 3 A meshing process window opens Then another window appears with information about the mesh generated Click View Mesh to visualize the mesh see Figure 2 Fi l e We ye EN F ae Ca ANE CN aS ERS Fi g MN 7 M a o alll m 1 Pa a m 7 _ i P Figure 2 Meshing by default Note that in the zone highlighted in Figure 3 elements are smaller than in the rest of the model This is because of the shape of the surface placed there When all meshing preferences are set by default as for this example the RFAST surface mesher is used In this way geometrical entities are meshed hierarchically first of all lines are meshed then the surfaces and finally the volumes The line elements size depends on the shape of surfaces as can be seen in this example Later on we will see an example using RJUMP mesher where element sizes are distributed differently Assign general mesh size witth default options 86 Figure 3 Meshing by default Zone where elements are smaller because of the surface shape 6 2 2 Assign size to points 1 Select Mesh gt Unstructured gt Assign size on points A window appears in which to enter the element size around the points to be chosen Enter 0 1 and click Assign 2 Select the point indicated in Figure 4 Press ESC 4 to indicate that the selection of points is finished and Close the window 3 S
135. x and press the Signal button the same effect is obtained by double clicking over the message with the left mouse button Ig NOTE If user clicks the right button over a message in the Mesh Errors window three options are displayed Signal problematic point More help or List The first option is the same as the Signal button while the List option presents a list of the problematic geometrical entities to make selection easier when performing some common procedures like sending the entities to a separate layer erasing the entities etc The More help option gives advice about to correct the geometrical model so the mesh can be generated MI NOTE 7he Mesh Errors window can be recovered while dealing with the model by selecting the Show errors option in the Mesh menu Meshing by default 146 id f E F i a Toa ii nA a ri po a a Pa oy ha 7 ior rf d z r F z i F r a E i Fi i hi ar F i F ee mm l 1 a j fi F tr a i r ra Bi e e g f i Signaling surface 124 9 2 2 Correcting surfaces 1 With the View gt Zoom gt In option in the menu or Zoom gt In on the mouse menu magnify the zone around surface 124 An enlargement of the zone around surface 124 2 Several line segments are superimposed over each other thus creating an incorrect surface boundary Select Geometry gt Edit gt Divide gt Lines gt Near point and then select point 17 to select it go to Contextua
136. y going to the Utilities menu selecting Preferences and then Automatic correct sizes inside Meshing branch Sometimes however this type of correction is not sufficient and it is necessary to indicate where on the mesh greater accuracy is needed In these cases GiD offers various options and methods allowing sizes to be assigned to elements To be sure that all the preferences are the ones used in this tutorial and get the same mesh as result set the default values for all the preferences Press Default values bottom button in the Meshing branch of the Preferences window and Close the window 2 The different options are None no size correction is made Normal a size correction is made according to the sizes of geometrical entities and the compatibility between meshing sizes of neighboring entities Hard the Normal correction is made and furthermore an automatic chordal error criteria is applied to assign sizes to surfaces which are the contours Element size assignment methods 85 of some volume in order to improve volume meshes 3 Similar options to Automatic correct sizes but to execute them manually one time can be found on Mesh gt Untructured gt Correct Sizes 6 2 1 Assign general mesh size witth default options To generate the mesh using the default options 1 Select Mesh gt Generate Mesh 2 A window appears showing the maximum element size This is the general mesh size that will be used for meshing the
137. yers option is not checked hence the new entities created will be placed in the layer to use otherwise the new entities are copied to the same layers as their originals 5 Click Select and select the surface of the wheel Press ESC 6 Select the two layers and click them On so that they are visible 7 Choose Render gt Flat from the mouse menu to visualize a more realistic version of the model Creating the volume of the wheel 61 Figure 27 Image of the wheel Now that the part has been drawn and the volumes created the mesh may be generated First we will generate a simple mesh by default Depending on the form of the entity to be meshed GiD performs an automatic correction of the element size This correction option which by default is activated may be modified in the Meshing gt Main branch of the Preferences window under the option Automatic correct sizes Automatic correction is sometimes not sufficient In such cases it must be indicated where a more precise mesh is needed Thus in this example we will increase the concentration of elements along the profile of the wheel by following two methods 1 assigning element sizes around points and 2 assigning element sizes around lines 1 Choose Mesh gt Generate mesh 2 A window comes up in which to enter the desired edge element size of the mesh to be generated Set a big size of 10 units to have a coarse mesh and click OK Generating a coarse mesh 62 E
138. ysis and introduction to customization 1 1 Models used in this manual In order to follow some of the tutorials included in this manual some files should be downloaded The models are located in GiD official webpage www gidhome com in Support gt Manuals section The models are packed in a zip file and classified by chapters INITIATION TO GiD 2 INITIATION TO GiD The philosophy of this tutorial is to get familiarized with GiD how to change the views of the model how to manage the Layers and other basic features Some of this features are both in the preprocessing and the postprocessing parts of GiD although the examples Shown are from the preprocessing one Many times the text will make reference to entities Almost all the options explained in this tutorial are valid both for geometrical and mesh entities although the examples used are often geometrical ones The topics in this tutorial are further explained in the Reference Manual We have selected some of the basic features to give to the user some basic tips to start working with GiD and make the rest of the tutorials 2 1 User interface For further information about GiD user interface please consult the General aspects gt User interface section in the Reference manual acos Project gidmodelbsic S Files View Geometry Utilities Data Mesh Calculate Help OB S SE234F BAlDO bya amp 3 9 g Pe A moose JZOR J 9 8 BAA IA SSE KES pws

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