GRID GENERATION AND ANALYSIS USING CATIA V5 - MBI-Wiki
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1. 16 Page NARENDRA KOMARLA Matr No 950763 GRID GENERATION AND ANALYSIS USING CATIA V5 Translational Displacement vector Translational disnlacement vi MITI MARA MAST 0 0515 0 0445 0 0385 0 03277 MASS 0 0192 0 0128 0 008541 On Boundary Figure 2 16 Principal stresses ur EIN ER POE n Ll E rag L 2 Par i th Stress principal tensor sym SA MPa a 723 E 40 5 ARA 36 ARRE E 11 9 aa 0 231 INA COSE SN 124 24 5 3h 7 4H Ad On Boundary Figure 2 17 EME UNI eM z GN Ry cure 7 Be s yo i ErTAL VS x NARENDRA KOMARLA Matr No 950763 17 Page S Scu Ve GRID GENERATION AND ANALYSIS USING CATIA V5 Precision Estimated local error I J 000155 D O00 138 000122 0 000107 3 185 005 44h5he 005 f5 178 00h 4 54e 005 306e 0 5 1 53e 005 a lfe 010 Figure 2 18 Report generation CATIA V5 generates a report once all parameters are defined The report is a html document which can be stored at any desired location Analysis Results Figure 2 19 The icon for report generation is Es Which can be found in the Analysis results toolbar 2 5 Stress calculation of a connecting rod utilizing symmetry boundary conditions The connecting rod is symmetrical about the X Z plane These conditions could be exploited to calculate stresses Utilising symmetric conditions would save computation time and res2. it is evident that the type of meshing is mapped or quantitative The next step is to define restraints in our model The restraints tab has to be used for defining the same which Is as seen in Figure 2 4 we l a a b to ERTAL VS x NARENDRA KOMARLA Matr No 950763 11 Page mus GRID GENERATION AND ANALYSIS USING CATIA V5 Figure 2 4 4 Since sliding motion prevails in the inner surface of the connecting rod 4 Surface slider restraint is applied there Surface Slider Name Surface Slider 1 2 Faces Ti 9 ok Figure 2 5 p A user defines restraint User restraints which is used in this case to restrict fee motion of the connecting rod Fix User defined Restraint Mame User defined Restraint 1 Axis System Type Global O Display locally Restrain Translation 1 Restrain Translation 2 a Restrain Translation 3 L Restrain Rotation 1 Restrain Rotation 2 Restrain Rotation 3 Figure 2 6 AE UNI lt ov t NARENDRA KOMARLA Matr No 950763 12 Page was xS40 Br gt Ep 4 s Py tery IS GRID GENERATION AND ANALYSIS USING CATIA V5 USER DEFINED RESTRAINT X Y TRANSLATION FIXED TO APPLY THIS CONSTRAINT A POINT HAS TO BE PICKED ON THE SURFACE Figure 2 7 SLIDING RESTRAINT Bs 2 INNER SURFACES A Figure 2 8 Once these two restraints are defined the model
3. Defined Materials Material Stahl Young Modulus 2e 011N m2 Poisson Ratio 0 266 Density 7860kg m3 Thermal Expansion 0 0000117 Yield Strength 2 5e 008M m2 Figure 3 11 EME UNI eM z GN Ry 27 Page SAD p J Bk y b x tara SS SS Scu Ve NARENDRA KOMARLA Matr No 950763 GRID GENERATION AND ANALYSIS USING CATIA V5 4 PLATE WITH A CIRCULAR HOLE IN ITS CENTRE 4 1 Introduction A plate with a circular hole in its centre is one of the most commonly used specimens to analyse pure tension shear or mixed mode loading analysis in plane stress and plane strain cases A plate under tensile loading is called a CT Compact Tension specimen which is the case being presented here Since the plate is symmetric about the X and Y axes symmetry conditions are exploited and one fourth of the model is analysed Following is the procedure 4 2 Procedure Open the part Lochscheibe2 CATpart which has been modelled for symmetry and assigned the properties of steel Figure 4 1 The first task is to generate an appropriate mesh for the part It is important to have a fine mesh in our area of interest which is near the hole ME UNDE CN A Sao y ep A NARENDRA KOMARLA Matr No 950763 28 Page sens y ON fray VS GRID GENERATION AND ANALYSIS USING CATIA V5 OCTREE Tetrahedron Mesh Global Local Quality Others Size 10mm fom Absolute
4. and available for structural analysis Once the element type has been selected appropriately the task becomes that of defining the model geometry as a mesh of finite elements Following are some particulars about shell elements gt Shell element can be either 1 D or 2 D plane element gt Boundary condition is applied at edge curve gt 3 D Structures that consist of thin surfaces are ideal structures for shell element application gt There is an enormous time saving when shell elements are used in place of 3 D solid elements Following are the most well Known 2 D shell elements Figure 5 1 Figure 5 1 The elements seen are linear triangular element Triangular element with middle nodes linear quadrilateral element and quadrilateral element with middle nodes serendipity element NARENDRA KOMARLA Matr No 950763 32 Page a GRID GENERATION AND ANALYSIS USING CATIA V5 5 2 Procedure To illustrate the use of shell elements consider the following example Open the Schalen CATPart from the download area Figure 5 2 The model consists of an extruded surface on which shell elements could be defined The material assigned is Steel similar to the previous cases The next step is to define the mesh for the part which is exclusive to this case The Advanced surface mesh in the Advanced meshing tools workbench is used to generate this mesh Global Parameters Mesh Type ee 9 Element t
5. control on mesh specifications The Advanced Meshing Tools workbench is composed of the following products FEM Surface FMS to generate a finite element model for complex surface parts FEM Solid FMD to generate a finite element model for complex solid parts Grids should be generated for Static and Frequency analysis Therefore in the first step one of these cases should be selected On selecting the Static analysis as an example the next step is to define the Mesh type and element type of the mesh NARENDRA KOMARLA Matr No 950763 GRID GENERATION AND ANALYSIS USING CATIA V5 2 3 Procedure Open the Pleuelstange 01 CATPart Connecting rod from the download area which is http www mtech uni wuppertal de 8080 MBI The compressed file FEM mit CATIA V5 zip can be found under the section CATIA FEM Buch which has to be downloaded New Analysis Case Static Analysis Frequency Analysis Free Frequency Analysis Keep as default starting analysis case Figure 2 1 Start Analyse amp Simulation Generative Structural Analysis Select the Static Analysis case Click on the OCTREE Tetrahedron Mesh to set the size of the mesh as seen in the Figure 2 2 OCTREE Tetrahedron Mesh Global Local Quality Others Analysis Manager Si 10mm A o si e Links Manager 1 ii Absolute sag 2mm Proportional sag 02 l Finite Element Model 1 pers e Nodes and Elements m
6. mesh A linear mesh is preferred because the curvature of the model is less Figure 3 2 NARENDRA KOMARLA Matr No 950763 GRID GENERATION AND ANALYSIS USING CATIA V5 OCTREE Tetrahedron Mesh Global Local Quality Others Size 7 95mm fera S Proportional sag 0 2 E used to access the mesh setting form Element type Linear po Parabolic dh Figure 3 2 Analysis Manager es Links Manager 1 Frequency Solution Parameters Number of Modes Finite Element Model 1 E E Nodes and Elements a su Wb Iterative subspace sn Properties 1 t Materials 1 O Lanczos L Dynamic Parameters 34 S d Frequency Case IT Maximum iteration number Ta be Restraints 1 Accuracy 0 001 El Mass Parameter Masses 1 Exclude i Frequency Case Solution 1 G Sensors 1 Figure 3 3 The parameters for frequency solution are set by double clicking on the frequency case in the model tree The required number of modes can be keyed in AE UNI a ov t NSAD p Ep s ON gra YS gt NARENDRA KOMARLA Matr No 950763 22 Page ws GRID GENERATION AND ANALYSIS USING CATIA V5 Other parameters Method Iterative subspace Lanczos only available if ELFINI Structural Analysis EST product is installed If Lanczos Method
7. ENERATION AND ANALYSIS USING CATIA V5 Global Parameters Mesh Type ers Element type Linear Parabolic Mesh Geometry Mesh size 10mm Quads only Minimize triangles LJ Directional mesh L Strip optimization Automatic mesh capture C Tolerance Umm aua ee Figure 6 3 The mesh is created similar to the previous procedure by entering parameters for the mesh size and offset after selecting the mesh type and the element type Figure 6 3 Once the 2D mesh is created the Mesh Transformations toolbar can be used to create a 3D mesh Volume elements Figure 6 4 gives an insight into this toolbar The unique feature of this transformation is that the numbers in the 3D mesh created is a constant Therefore as the size of the 3D element is decreased the mesh gets finer and vice versa Extrude mesher with translation and rotation is illustrated here Mesh Transfor EXTRUDE MESHER WITH TRANSLATION EXIRUDE MESHER WITH ROTATION EATRUDE MESHER WITH SYMMETRY EXIRUDE MESHER ALONG SPINE Figure 6 4 ME UNI SS Es e A SAD Br up N Z NARENDRA KOMARLA Matr No 950763 38 Page eman VE A x Erra Y SN GRID GENERATION AND ANALYSIS USING CATIA V5 Figure 6 5 MeshPart Advanced Surface Mesh 1 y Figure 6 6 NARENDRA KOMARLA Matr No 950763 39 Page NS3D p SN s
8. Element type Linear YO Parabolic A OCTREE Tetrahedron Mesh 1 Pleuelstange SF Properties 1 SF Materials static Case Figure 2 2 NO UNIV AN Re G NSAD p Br S NARENDRA KOMARLA Matr No 950763 10 Page ws s Py v Err VS GRID GENERATION AND ANALYSIS USING CATIA V5 This icon can be used to access the mesh setting form Figure 2 3 Parameters in this tab Size lets us choose the size of the mesh elements To know more about the Element Type you have to choose in the OCTREE Tetrahedron Mesh dialog box refer to Linear Tetrahedron and Parabolic Tetrahedron in the Finite Element Reference Guide Absolute sag Maximal gap between the mesh and the geometry Proportional sag Is the ratio between the local absolute sag and the local mesh edge length Absolute sag and Proportional sag could modify the local mesh edge length value We can give values for both Absolute sag and Proportional sag The most constraining of the two values will be used Element type lets us choose the type of element Linear or Parabolic There are various other options that can be used for mesh refinement in the OCTREE Tetrahedron Mesh dialog Local Quality and Others tabs can be used for these In our case the element size and Absolute sag values are entered to be 10mm and 2mm respectively The element type is linear A linear tetrahedral mesh will be the result Since the element type is entered as an input
9. GRID GENERATION AND ANALYSIS USING CATIA V5 445575 BERGISCHE 29 7 A 4724 UNIVERSIT T Yes WUPPERTAL NARENDRA KOMARLA M CME MENTOR Prof Dr Ing H B Woyand Fachgebiet Maschinenbau Informatik GRID GENERATION AND ANALYSIS USING CATIA V5 PREFACE CATIA V5 has been a versatile tool for CAX requirements in many engineering application The intelligible Graphics user interface of CATIA Icon driven approach is most appealing Many engineers who are familiar with other CAX tools can quickly adapt to CATIA V5 because of its user friendliness The objective of this manual is to familiarize the Advanced meshing tools and Generative structural analysis modules of CATIA V5 The manual is example driven so that the user can adapt similar approach with other parts too The manual is based on the book FEM mit CATIA V5 by Prof Hans Bernhard Woyand in German Language Screen shots have been liberally used to convey the meaning in an enhanced way The first chapter introduces steps in FEM and presents from Q amp A about meshing in particular The next three chapters discuss the use of the most common elements for generating meshes and presents analysis results in brief Structural and frequency analysis are discussed in these chapters The last two chapters give a peek into advanced mesh generation techniques such as Shell and hexahedron meshing It is urged to refer the CATIA V5 documentation to a maximum extent i
10. alised tool for Meshing and analysis however the platform is very user friendly and sufficient for carrying out any FEM analysis CATIA is an extremely powerful modelling tool Hence the model created in CATIA can directly be transferred to the Advanced Meshing tool workbench and after finalising the mesh solution and result interpretation could be done at a stretch 8 Analysis in CATIA V5 Overview a A note on CATIA V5 CATIA Computer Aided Three dimensional Interactive Application is a multi platform CAD CAM CAE commercial software suite developed by the French company Dassault Systems and marketed worldwide by IBM Written in the C programming language CATIA is the cornerstone of the Dassault Systems product lifecycle management software suite The software was created in the late 1970s and early 1980s to develop Dassault s Mirage fighter jet and then was adopted in the aerospace automotive shipbuilding and other industries More Information about CATIA V5 could be accessed using the following links http www ibm com CATIA http www 3ds com products CATI A welcome http en wikipedia org wiki CATI A There are numerous workbenches in CATIA V5 and each workbench has a purpose to achieve Grid generation is a part of the Advanced meshing tool workbench in CATIA V5 b User friendly environment CATIA Analysis provides designers and analysts with an intuitive user interface that meets their varied needs Since t
11. aterial is give a basic insight into Grid generation and analysis techniques using CATIA V5 1 2 Pre requisites The pre requisites of this course is modelling familiarity using any CAD tool Knowledge in CATIA V5 The basic concepts such as document windows standards and view toolbars would definitely be an added advantage Apart from this basic knowledge of Finite Element Methods would only help in understanding the contents better 1 3 Inspiration gt CATIA V5R18 Documentation gt FEM mit CATIA V5 Prof Hans Bernhard Woyand in German Language All CATIA models used or referenced in this material is from the above mentioned book The models can be downloaded from the following location http www mtech uni wuppertal de 8080 MBI In this webpage FEM mit CATIA V5 zip can be found under the section CATIA FEM Buch which can be downloaded Please note some of these parts have German names Some Q amp A about FEM FEA 1 What is Grid Generation Meshing A key step of the finite element method for numerical computation is mesh generation One is given a domain such as a polygon or polyhedron more realistic versions of the problem allow curved domain boundaries and must partition it into simple elements meeting in well defined ways There should be few elements but some portions of the domain may need small elements so that the computation is more accurate there All elements should be well shaped which means diff
12. cations The Advanced Meshing Tools workbench is composed of the following products FEM Surface FMS to generate a finite element model for complex surface parts FEM Solid FMD to generate a finite element model for complex solid parts NARENDRA KOMARLA Matr No 950763 GRID GENERATION AND ANALYSIS USING CATIA V5 4 What are the normal steps to be followed in Finite Element Analysis computation In particular what is Pre processing Finite Element Analysis essentially consists of the following 3 steps gt Pre processing gt Processing or Solution gt Post processing The Pre processing step is quite generally described as defining the model and it includes the following steps Define the geometric domain of the problem modelling Define the element type s to be used Define the material properties of the elements Define the geometric properties of the elements length area and the like Define the element connectivity mesh the model Define the physical constraints boundary conditions Define the loadings so eee ae Once the geometric domain modelling of the problem is defined using and CAD application CATIA V5 itself is preferable grid generation is the next process from Step 2 to Step 5 Once the grid is generated the model could be taken forward for stress computation The pre processing step is critical In no case is there a better example of the computer related axiom garbage i
13. ding node spacing hence element size and the software uses the prescribed information to generate nodes and elements A mapped mesh is restricted in terms of the element shape it contains and the pattern of the mesh A mapped area mesh contains either only quadrilateral or only triangular elements while a mapped volume mesh contains only hexahedron elements In addition a mapped mesh typically has a regular pattern with obvious rows of elements If a mapped mesh is desired we must build the geometry as a series of fairly regular volumes and or areas that can accept a mapped mesh In either meshing techniques the software user has some degree of control over the element mesh 3 Why ts meshing required Meshing is an essential pre processing step in Finite Element Analysis The final solution always depends on the quality of the mesh used during computation In simple terms Meshing means breaking up of a physical domain into simpler domains called the elements Usually there are Standard shapes into which the simpler domains are broken into The basic idea of a mesh generation scheme is to generate element connectivity data and nodal co ordinate data by reading in the input data for a few key points Advanced Meshing Tools allows us to rapidly generate a finite element model for complex parts whether they are surface or solid In other words we can generate associative meshing from complex parts with advanced control on mesh specifi
14. engine the connecting rod connects the piston to the crank or crankshaft Together with the crank they form a simple mechanism that converts linear motion into rotating motion The connecting rod is under tremendous stress from the reciprocating load represented by the piston actually stretching and being compressed with every rotation and the load increases to the third power with increasing engine speed Failure of a connecting rod usually called throwing a rod is one of the most common causes of catastrophic engine failure in cars Therefore the stress analysis of a connecting rod assumes high practical importance 2 2 Preparing the model for analysis Before entering the Generative structural analysis workbench the part has to be prepared for analysis The properties of the CAD part have to be defined i e Material isotropy etc in the Part design module itself For assigning properties right click on the part and select Properties The next task is to enter the Grid generation workbench in CATIA This workbench could be accessed by the Analysis and Simulation workbench Advanced meshing tool Following are the steps to be followed for entering the workbench Advanced Meshing Tools workbench represented by icon allows the user to rapidly generate a finite element model for complex parts whether they are surface or solid In other words we can generate associative meshing from complex parts with advanced
15. erent things in different situations but generally involves bounds on the angles or aspect ratio of the elements 2 Broad Classification gt Un structured mesh gt Structured mesh One distinguishes structured and unstructured meshes by the way the elements meet a structured mesh is one in which the elements have the topology of a regular grid Structured meshes are typically easier to compute with saving a constant factor in runtime but may e ME UNIV SM Ep NARENDRA KOMARLA Matr No 950763 4 Page ms lt GRID GENERATION AND ANALYSIS USING CATIA V5 require more elements or worse shaped elements Unstructured meshes are often computed using quadtrees or by Delaunay triangulation of point sets however there are quite varied approaches for selecting the points to be triangulated Another classification for meshing is the auto meshing gt Free mesh gt Mapped mesh Before meshing the model and even before building the model it is important to think about whether a free mesh or a mapped mesh is appropriate for the analysis In free meshing the user specifies a general qualitative mesh description ranging from coarse to fine with 10 or more gradations between the extremes The software then generates the mesh accordingly Therefore a free mesh has no restrictions in terms of element shapes and has no specified pattern applied to it In mapped meshing the user specifies quantitative information regar
16. forced Displace Name Enforced Displacement 1 Figure 4 6 An enforced displacement E of 0 023mm is applied on the face on which the second slider restraint is applied The enforced displacement icon could be accessed from the loads toolbar 4 3 Results The model is now ready for analysis Similar to the previous steps the computation for the static case solution is started from the icon Figure 4 7 of ME UNIVE Ko VA A A lt e r NARENDRA KOMARLA Matr No 950763 31 Page e MG GRID GENERATION AND ANALYSIS USING CATIA V5 5 MESHING WITH SHELL ELEMENTS 5 1 Introduction Probably the most critical step in application of the finite element method is the choice of element type for a given problem The solid elements discussed till now are among the simplest elements available for use in stress analysis Many more element types are available to the finite element analyst Commercial software systems have no fewer than 140 element types The differences in elements for stress analysis fall into three categories gt Number of nodes hence polynomial order of interpolation functions gt Type of material behaviour elastic plastic thermal stress etc gt Loading and geometry of the structure to be modelled plane stress plane strain axis symmetric general three dimensional bending and torsion In case of shell thin curved plate structures specialized elements are required
17. g fork is an acoustic resonator in the form of a two pronged fork with the prongs tines formed from a U shaped bar of elastic metal usually steel It resonates at a specific constant pitch when set vibrating by striking it against a surface or with an object and emits a pure musical tone after waiting a moment to allow some high overtones to die out The pitch that a particular tuning fork generates depends on the length of the two prongs Its main use Is as a Standard of pitch to tune other musical instruments 3 2 Analysis Steps Frequency analysis on a tuning fork is carried out using CATIA V5 as illustrated ahead The CAD model of the fork is opened and the Generative Structural Analysis module is navigated through Start Analysis amp Simulation Generative Structural Analysis Frequency analysis is selected out of the 3 options available in Generative Structural Analysis Open the Stimmgabel 01 CATPart Tuning fork from the download area New Analysis Case Frequency Analysis Free Frequency Analysis Keep as default starting analysis case EM OK Cancel Figure 3 1 The subsequently step is to generate a 3D mesh on the model This is done as discussed in the previous case A finer mesh as compared to the initial case is chosen because the area of cross section is relatively low in this case A size and absolute sag value of 7 95 and 1 272 are entered respectively The element type is a linear tetrahedral
18. he user interface is a natural extension of that in CATIA it is particularly easy for CATIA users They obtain a realistic understanding of the mechanical behaviour by quickly reviewing design characteristics in a digital mock up DMU environment The CATIA V5 tools and environment that are common to all CATIA applications ABAQUS CAE for CATIA and partner solutions eliminate the problem of lost productivity associated with using multiple applications c Fast design analysis loops CATIA Analysis is an integral part of CATIA The analysis specifications are an extension of the part and assembly design specifications and the analysis is performed directly on the CATIA geometry It is therefore simple and convenient to perform an analysis to help size parts and compare the performance of different design alternatives The impact of design changes can be rapidly assessed with automatic updates Designers using CATIA Analysis will naturally use analysis as part of their design process affording them a greater understanding of how their designs perform and improving their ability to deliver the right design the first time NARENDRA KOMARLA Matr No 950763 7 Page we GRID GENERATION AND ANALYSIS USING CATIA V5 d Multidiscipline collaboration CATIA Analysis Supports concurrent engineering allowing users to work closely together and avoid rework Designers and analysts can collaborate since they have access to the same environment elim
19. inating data transfer rework and the need to maintain multiple applications for design and analysis The CATIA Analysis environment also allows method developers to create templates that designers can routinely use to perform standard types of analysis e Knowledge based optimization The CATIA Analysis products leverage the native CATIA knowledge based architecture They allow designs to be optimized by capturing and studying the knowledge associated with part design and analysis The reuse of analysis features and the application of knowledge based rules and checks ensure compliance to company best practices Automation of standard analysis processes through the use of knowledge ware templates dramatically improves the efficiency of the design analysis process f Industry proven performance The speed with which analyses can be performed with CATIA Analysis often surprises designers and simulation experts familiar with other applications The time it takes to create the finite element model solve it and display results can be a matter of minutes The robust built in finite element solver and mesh generators balance both accuracy and speed The adaptive meshing capability automatically adjusts the mesh to obtain accurate results without time consuming manual involvement NARENDRA KOMARLA Matr No 950763 GRID GENERATION AND ANALYSIS USING CATIA V5 2 STRUCTURAL ANALYSIS OF AN IC ENGINE CONNECTING ROD 2 1 Introduction In an IC
20. is and Simulation Generative Structure Analysis The results can be analysed through the well known Image toolbar The von mises stress Figure 5 8 and the deformed mesh Figure 5 9 are seen here Von Mises stress nodal wall M m 1 1 28 008 1 0184 0 amp 8 ko 007 7 8 e 007 755 007 Hh Rdlasr 007 4 535 007 3 125007 2 3le 007 1 1985 007 B 07er 005 On Boundary Figure 5 8 Figure 5 9 ME UNIV ON NS3D p X Ep S bj Ryan YS lt NARENDRA KOMARLA Matr No 950763 36 Page ns GRID GENERATION AND ANALYSIS USING CATIA V5 6 MESHING WITH HEXAHEDRON ELEMENTS 6 1 Introduction The generalization of a quadrilateral in three dimensions is a hexahedron also known in the finite element literature as brick A hexahedron is topologically equivalent to a cube It has eight corners twelve edges or sides and six faces It is a volume element Finite elements with this geometry are extensively used in modeling three dimensional solids Figure 6 1 Figure 6 1 shows 8 noded tri linear 20 noded serendipity and 27 noded hexahedral elements which are commonly used in practice 6 2 Procedure To illustrate the use of hexahedral elements consider the following example Open the Hexaeder CATPart from the download area Figure 6 2 ME UNIV M 4 Og KA 4 NSAID p PN A s Lara IS NARENDRA KOMARLA Matr No 950763 37 Page sens 7 GRID G
21. is selected the Shift option appears which computes the modes beyond a given value Auto 1Hz 2Hz and so forth Auto means that the computation is performed on a structure that is partially free Dynamic Parameters Maximum iteration number Accuracy Mass Parameter lets the user take into account the structural mass This check box lets us exclude the structural mass from the total mass summation when computing the solution of a frequency case with additional mass If the structural mass parameter in a frequency case is excluded without additional masses frequency case without masses set an error occurs while computing the solution If the frequency case does not contain any masses set we do not select this option The next step is to define restraints to our tuning fork Restraints 2 Figure 3 4 d This icon can be used to define clamp forces Two clamp forces Clamp 1 2 faces and Clamp 2 1 face are defined as seen in the pictures below NARENDRA KOMARLA Matr No 950763 23 Page ke de GRID GENERATION AND ANALYSIS USING CATIA V5 CLAMP 1 Figure 3 5 Once these parameters are defined the part can be analyzed by clicking on the compute icon Analysis Case Solution Selection Selection by Restraint Figure 3 6 The compute command calculates the unknown parameters All Mesh only Analysis Case Solution Selection and Selection by Restraint can be selected from the drop down menu Al
22. l can be selected as a safe option The computation will consume some system time and resource to complete Once it is completed The Image toolbar can be used to find the parameters as discussed ahead Figure 3 7 ME UNI EN amp A t 4 540 Byr 278 y tera VS sy 2s 3 ma sem NARENDRA KOMARLA Matr No 950763 24 Page GRID GENERATION AND ANALYSIS USING CATIA V5 3 3 Results A Frequency Case j Restraints 1 Masses 1 sa Frequency Case Solution 1 53 gt DISPLACEMENT Pis Deformed mesh 1 DEFORMATION Sa lb Von Mises stress nodal values i VON MISES STRESS Va or PRECISION b Stress principal tensor symbol 1 PRINCIPAL STRESS ks Translational displacement vector 1 Figure 3 7 The model tree updates itself for the Frequency case solution when each button is pressed Fig In frequency analysis the Transitional displacement Vector is of special interest Double clicking on Transitional displacement vector the following box appears Image Edition 808 758 815 857 837 15 4855 28 5271 55 5369 43 5453 15 9732 52 104924 LO Ch Ln e lu pu H More gt Figure 3 8 Since we had selected 10 modes the frequency for each mode is displayed in the editor Each case can be analyzed separate
23. looks as seen in the picture above The next step is to define loads or forces on the model which can be done by the Loads toolbar Figure 2 9 Loads Q 9 CE Figure 2 9 ME UNDP CN SA 13 Page scs s Dr tera V NSAD p NN Br NARENDRA KOMARLA Matr No 950763 GRID GENERATION AND ANALYSIS USING CATIA V5 Distributed load can be assigned through the Icon Distributed Force Type Global E Display locally Force Vector Norm 10000N x on v 10000N Z ON DISTRIBUTED LOAD 10000N m Q9 ok Scancell APPLIED ON 2 FACES Figure 2 10 A distributed load of LOOOON is applied in the Y direction as seen in Figure 2 10 mm LET mmm LI Once these parameters are defined the part can be analyzed by clicking on the compute icon Mesh Only Analysis Case Solution Selection Selection by Restraint Figure 2 11 The compute command calculates the unknown parameters All Mesh only Analysis Case Solution Selection and Selection by Restraint can be selected from the drop down menu All can be selected as a safe option The computation will consume some system time and ME UNI py 2M z NP Ry NARENDRA KOMARLA Matr No 950763 14 Page nan VSD Br N Eh 2 y duy tery IS GRID GENERATION AND ANALYSIS USING CATIA V5 resource to complete Once it is completed The Image toolbar can be u
24. ly The analysis tools toolbar Figure 3 9 is used for this purpose i AE UN y gt KS E gt NSAD p Ep g M NARENDRA KOMARLA Matr No 950763 25 Page we 7A Pr NI 4 RTAL ys GRID GENERATION AND ANALYSIS USING CATIA V5 Analysis Tools Figure 3 9 The Button Sa Animate displays the animation of the tuning fork displacement at a particular frequency Frequency at any required mode The deformation and the Transitional displacement vector for the first two frequencies 713 84 Hz and 808 759 Hz are shown in Figure 3 10 Figure 3 10 Individual information In certain nodes elements of particular interest could be accessed by the e icon Once the button is pressed a node can be selected and detailed information regarding the same is output on the screen For example the information at node 115 will look as seen in the picture ahead Figure 3 11 ME UNIV se Ww Ven Ka A E NARENDRA KOMARLA Matr No 950763 26 Page oie dm a Pr M ERTAL ys GRID GENERATION AND ANALYSIS USING CATIA V5 Information gt Selected node 115 Coordinates mm 15 13 734 Value mm 4538 89 22393 126 994 gt Object name Translational displacement vector 1 Values provider Frequency Case Solution 1 Occurrence 2 Frequency 808 759Hz Display On deformed mesh On boundary Over all the model Extrema Values Min 0 mm Max 7258 49 mm Filters 3D elements Components All
25. n x ME UNI Si ny v Penn yv ou PP A scones GRID GENERATION AND ANALYSIS USING CATIA V5 The mesh is parametric which is typical of CATIA and can be edited freely If the start angle is changed to 90 degrees the model acquires shape as seen in Figure 6 7 It can be observed here that the number of elements remain the same and thereby the mesh gets denser Figure 6 7 Therefore the Mesh transformations can be a useful and powerful tool to generate 3D meshes using volume elements Once the mesh is created on the required geometry further steps are similar as mentioned in the previous sections EME UNI SS Ry NARENDRA KOMARLA Matr No 950763 40 Page man NSD p X Ep y gt y bj fray NS GRID GENERATION AND ANALYSIS USING CATIA V5 7 ACKNOWLEDGEMENTS am highly indebted to Prof Dr Hans Bernhard Woyand Bergische University Wuppertal for giving me an opportunity to work on this project The work helped me to get an insight towards the structural analysis module in CATIA V5 and achieve academic targets as well It is said that What the teacher is is more important than what he teaches Prof Woyand is a excellent individual and has been an immense source of inspiration for his students to emulate would also like to thank Mr David Elmar for his suggestions The project also gave me an opportunity to get familiarised with the practical side of Finite element analysis It ha
26. n garbage out A perfectly computed finite element solution is of absolutely no value if it corresponds to the wrong problem Therefore a high quality optimised grid always leads to a high quality final output 5 More about meshing A very important aspect of meshing a model with elements is to ensure that in regions of geometric discontinuity a finer mesh smaller elements is defined in the region This is true in all finite element analyses structural thermal and fluid because it is known that gradients are higher in such areas and finer meshes are required to adequately describe the physical behaviour In mapped meshing this is defined by the software user Fortunately in free meshing this aspect is accounted for by the software 6 What are the current methods or tools available for Grid generation and Analysis Commercially many tools are available for Grid generation Part and assembly modelling pre processing processing and post processing could be performed using all leading CAD tools like Pro Engineer Unigraphics Solidworks CATIA V5 etc There are specialised solver tools such as ANSYS ABAQUS MSc Nastran etc which could effectively be used for meshing Apart from these Hypermesh is another CAE tool which specialises exclusively in meshing NARENDRA KOMARLA Matr No 950763 6 Page mime GRID GENERATION AND ANALYSIS USING CATIA V5 7 Why ts Grid generation using CATIA V5 a good option CATIA is not a speci
27. n order to deepen tool knowledge The documentation is complete and an in dispensable contrivance NARENDRA KOMARLA Matr No 950763 GRID GENERATION AND ANALYSIS USING CATIA V5 CONTENTS 1 Introduction 4 Objective of this course Pre requisites Inspiration 1 1 1 l Some Q amp A about FEA FEM AUNE 2 Structural analysis of an I C engine connecting rod 9 Introduction Preparing the model for analysis Procedure Results Stress calculation of a connecting rod utilizing symmetry boundary conditions Buckling of the connecting rod NINNNN N OU RON 3 Frequency analysis of a Tuning fork 21 3 1 Introduction 3 2 Analysis steps 3 3 Results 4 Plate with circular hole in its centre 28 4 1 Introduction 4 2 Procedure 4 3 Results 5 Meshing with shell elements gt 32 5 1 Introduction 5 2 Procedure 5 3 Results 6 Meshing with hexahedron elements J 37 6 1 Introduction 6 2 Procedure 7 Acknowledgements 41 8 References 41 NARENDRA KOMARLA Matr No 950763 GRID GENERATION AND ANALYSIS USING CATIA V5 1 INTRODUCTION 1 1 Objective of this course The objective of this course m
28. ource It may not be relevant in this case but is very important in case of huge models with numerous elements and nodes naturally ME UNDP SS M Ep s Ka E 7700 i ErTAL VS ue NARENDRA KOMARLA Matr No 950763 18 Page ey A gs GRID GENERATION AND ANALYSIS USING CATIA V5 Open the Pleuelstange 02 CATPart from the download area Figure 2 20 Similar to the previous case the surface slider restraint and the user defined restraint are applied to the CAD model as seen in Figure 2 20 SURFACE SLIDER RESTRAINTS USER DEFINED RESTRAINT FIX SYMMETRICAL ABOUT X Z PLANE HENCE ANY POINT ON THIS PLANE CAN BE SELECTED FOR FIX Figure 2 21 The axial distributed force in the longitudinal direction is then applied to the model as seen Figure 2 22 The force magnitude is 10 000N ME UNI ee e Ka E 7A A x ERTAL V NARENDRA KOMARLA Matr No 950763 19 Page ven est GRID GENERATION AND ANALYSIS USING CATIA V5 Figure 2 22 symmetry conditions are comparable Once these parameters are defined the model may be computed for the un known parameters similar to the previous section The results from the previous model and the half model utilising NARENDRA KOMARLA Matr No 950763 AE UNI Vp NT E gt x ERTAL V La iter AP Or SEV a g e Scio ve GRID GENERATION AND ANALYSIS USING CATIA V5 3 FREQUENCY ANALYSIS OF A TUNING FORK 3 1 Introduction A tunin
29. s aroused keen interest in me to work further in this area Narendra Komarla Matriculation No 950763 8 REFERENCES FEM mit CATIA V5 Prof Hans Bernhard Woyand The manual is based on this book Fundamentals of Finite Element Analysis D V Hutton CATIA V5R18 User s Manual was liberally used during the course of this work The documentation provides an extensive insight into every module of CATIA V5 S ali S Me ei f NARENDRA KOMARLA Matr No 950763 41 Page E
30. sag 2mm us Proportional sag 0 2 a Element type C Linear de Parabolic Figure 4 2 A parabolic Octree tetrahedral mesh is first defined similar to the previous cases Since a finer mesh is required near the hole a local mesh can be defined there As per Figure 4 3 a local mesh of element size 5mm is defined The edge highlighted is selected for the supports A smaller tetrahedral local mesh can be seen in the region of interest now Local Mesh Size Name Local Mesh Sizel Supports ETR Value 5mm A OK Cancel Figure 4 3 The next task is to assign the boundary conditions for our model This is done in the usual way by defining the surface sliders for the model ME UNI e KA NARENDRA KOMARLA Matr No 950763 29 Page NSAD p syn 55 yv Pepa Ss x ou NS v I SCHUM GRID GENERATION AND ANALYSIS USING CATIA V5 Since the part is symmetric about the X and Y axes and Is being treated as a Plane strain case where the Z dimension is large restraints are applied as seen in Figure 4 2 Figure 4 4 To restrain free motion of the part the face as seen in Figure 4 3 is also constrained Figure 4 5 ME UNI M Er N bj fray NS NSD p X 7 JA lt NARENDRA KOMARLA Matr No 950763 30 Page ns GRID GENERATION AND ANALYSIS USING CATIA V5 The succeeding step is to define the loads Loads can be specified as forces or displacements En
31. sed to find the parameters seen in the image below Figure 2 12 Static Case ida Restraints 1 ia Loads 1 s i Static Case Solution 1 r Deformed mesh 1 Eg DISPLACEMENT s Von Mises stress nodal values 1 A Translational displacement vector 1 p m PRECISION s Stress principal tensor symbol 1 DEFORMATION VON MISES STRESS PRINCIPAL STRESS em Estimated local error 1 Figure 2 12 The model tree updates itself for the Static case solution when each button in the Image toolbar is pushed For static analysis the deformation Von mises stress principal stress displacements and Precision all results are important To apply the bearing load Analysis Tools Figure 2 13 The Button Animate displays the animation of the connecting rod The displacement pattern may be animated and for better visualization and understanding 2 4 Results Mesh The node and element numbers can be seen by clicking on the element of our interest ork UNI S Ry A SED 7 a if By NARENDRA KOMARLA Matr No 950763 ysi Z 15 Page ti AN ay 4 RTAL y GRID GENERATION AND ANALYSIS USING CATIA V5 Figure 2 14 Von Mises stress wan Mises stress rmadal vali Fra GANG AESTON e A en Figure 2 15 d LT SEES ARCEM t CELA ARE ae E er a Ce ee pe v SCHUW ME l Mile NT S at WL AN i gt gt OW
32. ype s Linear Parabolic Mesh Geometry Mesh size 20mm s Offset Omm L Quads only Minimize triangles L Directional mesh LI Strip optimization Automatic mesh capture Toleran cel Omm femi Cancel Figure 5 3 ME UNI a ov t NS3D p Ep Z NARENDRA KOMARLA Matr No 950763 33 Page mi sy y s Laps ferry VS GRID GENERATION AND ANALYSIS USING CATIA V5 Figure 5 4 The pre defined 2D property has to be assigned to the surface This can be done by simply selecting the surface as the supports Figure 5 5 Figure 5 5 Restraints are applied on one edge of the surface as seen in Figure 5 6 The highlighted edge is the selected edge where the clamp is applied UN y QUU CA NT Ku so XSAD p Sa KN NARENDRA KOMARLA Matr No 950763 34 Page eae GRID GENERATION AND ANALYSIS USING CATIA V5 e OK S Cancel na Figure 5 6 Distributed forced are applied on the model Figure 5 7 The highlighted edge is selected for the Supports A force of 1000N is applied in this case Figure 5 7 ME UNIV S ara NARENDRA KOMARLA Matr No 950763 35 Page umos v fray VS S SAD B 7 S RV GRID GENERATION AND ANALYSIS USING CATIA V5 5 3 Results n Once these parameters are defined we can now enter the Generative Structural Analysis workbench through the main menu which is Start Analys
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