Generative Part Structural AnalysisCATIA Training FoilsVersion 5 Release 9June 2002EDU-CAT-E-GPS-FF-V5R91Objectives of the courseIn this course you will learn how to perform Static and Modal Analyses(create analysis documents, compute and visualize) on a single Part.Targeted audienceCATIA V5 UsersPrerequisitesMechanical DesignFundamentals in CATIAV5Generative Part Structural Analysis1.5 days2Table of Contents (1/2) 2.7. Beam elementsp.40 4.2. Images Layoutp.604.8. Mesh Adaptativity4.9. Knowledgeware3Table of Contents (2/2)4In this lesson, you will learn about the Generative Part Structural Analysis Workbench by : Accessing The Workbench User Interface User Settings1. Introduction to GPS Analysis51.1. Accessing the WorkbenchIn this lesson, you will learn about the Generative Part Structural Analysis Workbench.Be sure that the Part being studied has a material applied. This action can only be performed in the Part Design Workbench3- Modal or Static Analysis. A new CATAnalysis document is created.2- Analysis & Simulation1- Start61.2. User Interface - ToolbarsRestraintsExternal Storage ManagementAnalysis reportingLoadsModel ManagerComputeImagesVirtual parts Manager and mass7User Interface - IconsImage CreationDeformationStress Von MisesDisplacementRestraints ApplicationClampMechanical RestraintAdvanced RestraintResults VisualizationAnimateCut Plane AnalysisDeformation Scale FactorSearch Image ExtremaInformationsImage LayoutComputationComputeLoads ApplicationPressureForceAccelerationForce DensityEnforced DisplacementTemperature fieldMass EquipmentMassAnalysis ResultsBasic Analysis ReportHistoric Of ComputationsListingSolver ToolsStorage LocationClear StorageTemporary Data DirectoryModel managerTetrahedron, Octree and Beam meshingElement type and local meshSolid propertyShell propertyBeam propertyModel CheckVirtual parts managerVirtual partsPeriodicity conditionsNew !New !New !8Analysis TreeAssociated Generative PartPre-Processing InputImages of ResultsUser Interface - Specification TreeMesh parts PropertiesExternal StorageMesh parts Specifications9This enables you to faster access the analysis workbench.1.3. User Settings - Shortcut Of Analysis Icon2- Transfer “Generative Structural Analysis” from Available to Favorites1- Select “Customize” from Tools menu3- Access Analysis Workbench through this icon10In Part Design Workbench, customize Render Style by adding material visualization. This will also enable you to view analysis images in average-iso visualization mode.We will activate Materials so that material render styles are displayedUser Settings - Customizing View Modes2- Click on “Apply Customized View”3- Activate “Materials” and click OK.1- Select Render Style from the View menu11This enhances the visualization of selected faces.User Settings - Highlighting Faces and Edges1- Select “Options” from the Tools menu2- Click “Display”3- Click “Navigation”4- Activate “Highlight faces and edges”12User Settings - Show / No Show Visualization 1- Select “Options” from the “Tools” menu3- Click “Tree”2- Click “Display”4- Activate Visualization of Show / NoShow13In this lesson, you will learn how to create a new Analysis Document, how to save it and how to define Restraints and Loads on a Part. Create a New Analysis DocumentSave Analysis DocumentsDefine RestraintsDefine LoadsAdvanced Pre-Processing Tools2. Static Analysis Pre-Processing14General Process for a Static AnalysisEnsure that part has material defined thenOpen Static Analysis WorkbenchApply Restraints to the modelApply Loads to the modelAnalyze the ResultsRefine the AnalysisPerform ComputationCreate Images15A Material must be applied to the studied Part. This can only be peformed in the Part Design Workbench.1- Click on the Material icon2- Select a Material4- Apply2.1. Document Creation - Assigning Materials5- Check3- Select a Part (on the geometry or in the tree)16New Analysis Documents, entitled CATAnalysis files, can be created in various ways.There are 3 ways to create a new Analysis Document : Document Creation -Three WaysWorkbench IconFile menuStart menu17Here is how to create a new Analysis Document using the Start menu.Document Creation - Using Start Menu1- Click “Start”2- Click “Generative Structural Analysis”3- Select Static or Frequency Analysis18There are various ways to save an Analysis Document and its parent documents. It is important to achieve this correctly with an assembly analysis document, for the assembly has to be properly linked with all the parts it is made from.Only those documents that have been modified will be saved or proposed for the saving.2.2. Saving an Analysis DocumentSave will save the active Analysis DocumentSave As. is similar to Save, but it allows you to specify the name and folder for the active Analysis DocumentSave All will propose saving all open documents and children of these documents19Save Management is an easy way to save all modified documents under user-specified names.All modified open documents will be proposed for saving, regardless of which document is activeDocument Saving - Under Specified Names1- Select “Save Management”2- Specify which documents to be saved20“Send To” is an easy way to save all linked documents in a user specified directory.Available filesFiles that will be savedDocument Saving - “Send To” MechanismUse this option if you want the directory structure of the selected files list to be duplicated. Else the selected files will be copied directly under the target directory.1- Select “Send To” & “Directory”2- Use these arrows to switch selected files between “Can be copied” and “Will be copied”4- Select the target directory3- Click here to modify the selected target name2- Use theses arrows to switch all the files between “Can be copied” and “Will be copied”212.3. Mesh-parts management Mesh creation & destructionNew R9To create or modify mesh-parts, click on the appropriate mesh-part toolbar iconOctree tetrahedron mesh for solid geometry1. Select the mesh part in the tree.2. Contextual menu, and Delete.Octree triangle mesh for surface meshBeam meshing for wire-frame geometryWe can also delete a mesh part created from an automatic mesher or FMS1. Select the geometry to mesh.2. Select the corresponding mesh type.3. Enter mesh specifications22Mesh-parts management Properties managementNew R91. Select the appropriate property type.2. Select the part geometry entity (PartBody or OpenBody) in the tree.3. Enter property specifications as the case may be.A mesh part must have only one single property.As for mesh parts, we can also delete properties.Once the mesh part is created, we have to define its property23Mesh-parts management Model Check commandNew R9The Model Check command can help the user understanding the Design-Analysis links.qThanks to the list of all the mesh parts and properties.qHighlights the corresponding features.Just before compute, we can check the consistency of the FEM model :qMissing properties.qMissing material.qMissing support.qDiagnostic problems.After modificationsDiagnostic : Check for Property and Material missing and redundance. 24Mesh-parts management Analyze of parts made of several bodiesNew R9We can analyze parts which have several GSD bodiesqEach body has its own material.qSeveral mesh parts will be created (one for each body).qThen, we can apply different thicknesses for each mesh part.Several bodiesSeveral mesh parts25Clamps are restraints applied to surface or curve geometries, on which all nodes are to be blocked in the subsequent analysis.2.4. Define Restraints - Clamps1- Click on the “Clamp” Icon in the “Restrain” Toolbar2- Select the geometry support(s) (Surfaces or Edges). 3- Click “OK”Symbols associated to a null translation in all directions of the selected geometry are displayed.A Clamp object appears in the Specification Tree under the active Restraints objects set.Any selectable geometry is highlighted when you drag the cursor over it.26Surface slider (3Tr. & 1Rot.), Slider (1Tr.), Sliding pivot (1Tr. & 1Rot.), Ball joint (3Rot.) and Pivot (1Rot.).Surface slider can be directly applied on surfaces whereas other Restraints must be applied on a virtual part (See 5.4.)1- Click on Surface Slider IconSymbols on GeometryFeatures TreeDefine Restraints - Mechanical Restraints2- Select the Geometry Support(s) (Surfaces)3- Click “OK”27Advanced Restraints are generic restraints allowing you to fix any combination of available nodal degrees of freedom (dof) on arbitrary geometries.2- Select axis typeDefine Restraints - Advanced Restraints1- Select the support(s) (Surfaces or Edges)3- Activate degrees to be fixedThe rotation degrees are relevant only for structural element meshes (i.e. shell elements), or Virtual Parts.28Iso-static Restraints are Statically Definite Restraints allowing you to simply support a Body.Define Restraints - Iso-static Restraints1- Click on the “iso-static restraints” Icon2- Select a geometry3- Click OK29Pressures are intensive loads representing uniform scalar pressure fields applied to surface geometries, hence the force direction is everywhere normal to the surface.1- Click on the “Pressure” IconSymbols representing the Pressure Loads are displayed.A Loads object appears in the Features Tree under the active Loads objects set.2.5. Define Loads - Pressure Loads2- Select the geometry support(s)(Surfaces). Any selectable geometry is highlighted when you drag the cursor over it. 4- Click “OK”3- Specify a pressure value or Open a Data File for mapping30Distributed Forces (Moments) are force systems statically equivalent to a given pure force (couple) resultant at a given point, distributed on a virtual part or on a geometric selection.Define Loads - Distributed Forces and Moments1- Select support(s)(Surfaces or Edges)2- Select axis type3- Specify force31Accelerations are intensive loads representing mass body force (acceleration) fields of uniform magnitude applied to parts.Define Loads - Acceleration (Gravity Body Forces)1- Select support(s)(Surfaces or Edges)2- Select axis type3- Specify vector32Rotation Forces are intensive loads representing mass body force (acceleration) fields induced by rotational motion applied to parts.Define Loads - Rotation Forces1- Select support(s)(Surfaces or Edges)2- Select axis3- Specify anglevelocity and acceleration (if necessary)33Force Densities are intensive loads representing line (surface) traction fields or volume body force fields, of uniform magnitude, applied to either curve (surface) geometries, or to parts.Define Loads - Force Densities1- Select support(s)2- Select axis type3- Specify vectorOrOpen a data file for mapping an external load34Enforced Displacements are equivalent loads applied to support geometries, resulting for the subsequent analysis in assigning non-zero values to displacements in previously restrained directions.An Enforced Displacement object is by definition associated to a Restraint object.Define Loads - Enforced Displacements1- Select restraint2- Enter values for each restrained dof35Instead of specifying each component of the force vector, you can simply define the force direction by using the compass. This will ensure that the force is defined relatively to the part, whatever its positioning.2.6. Advanced Pre-Processing Tools - Force with Compass1- Click on the loads icon2- Select support and specify force vector norm3- Drag the compass by handling the red square and drop it on the appropriate surface4- Use Compass to define vector direction36Instead of using the global axis system, you can use an implicit one if you want your pre-processing to be defined with respect to the part. You can also specify a user defined axis system if you have created one in Part Design.In that case, the dof directions of an advanced restraint, or the components of a force, will be processed with respect to the the specified Axis system. Their interpretation will further depend on your Axis Type choice.The restrain rotations are available only with surfacic geometry. Advanced Pre-Processing Tools - Axis Systems1- Select a user defined axis system type3- Select axis system local orientation4- Fix dofs (in Advanced Restraint case)NB: Rotations are available with shells, but not with solids. 2- Select an existing axis system in the features tree37New !Advanced Pre-Processing Tools Pre-processing on pointsWe can apply pre-processing specifications on points and vertexWe can apply it for Loads, restraints or Masses.It is available on different types of support :VertexPoints followed by FMSPoints followed by Octree mesher1. Create a GSD point2. Mesh the part with the constrained point3. Apply distributed force38Advanced Pre-Processing Tools Mass setsMass sets can be included in a static case :Used for loadings based on inertia effect (acceleration, rotation).Take into account the mass modeling capabilities in the load definition.1. Insert a new Static Case2. Select Masses :- If there is already a Mass set in the first Static case, you can select it as Reference.- If there is no Mass set, select New.New R939New R92.7. Beam elements : wire-frame mesherAssociativity with the Generative Shape Design Workbench.qUse JOIN capability to build complex wire-frame feature.qAn automatic mesh part generation is made if an external view has been defined.1.Design your wire-frame structure in GSD.2.Use JOIN command if there are several beams. Apply material on the Join entity created.3.Do an external view and go to GPS, then you will have to change default mesh properties created.4.Or go directly to GPS and click on Beam mesher.5.Do Mesh Visualization ( or compute Mesh Only).40New R9Beam elements : Beam properties definitionApply a property on a single beam or on a Join featureqSelect the Beam property icon.qEnter the beam caracteristics.After clicking OK, a local axis system is diplayed at the centroid, showing the section orientation.The orientation point must not be colinear with the beam axis, even if the section is axisymetric !41New R9Beam elements : Beam pre-processing and static analysisPre-processing on beam elementsqPut GSD points in No-Show mode, so as to keep from selecting them (else : mesh errors generation).qPut a clamp to one of the vertex.qApply a distributed force to the other vertex.Compute and Post-processing on beam elementsqWe can display deformation and displacements (other post-processing options with EST capabilities).In GAS, we can also do hybrid analysis with solid-shell-wireframe geometry.42In this lesson, you will learn how to compute a Static Analysis.Specifying External StorageComputing3. Results Computation of a Static Analysis43All ELFINI Solver computations are systematically stored in a structured way out of core memory, on an external file which paths name is External Storage.The link between the CATAnalysis document and the External Storage is maintained after the end of a session, in a way similar to the link between a CATPart and the associated CATAnalysis document. It is recommended that you locate your external storage where there is sufficient space. There are two solutions to Modify the storage path which are : the toolbar buttons or the specification tree.3.1. Specifying External Storage (1/5) 1- Click on the Storage” icon in the Solver Tools toolbarThe “Elfini Storage Location” dialog box is displayed3- Select a path for the External Storage directories4- Click Save2- Click the Modify button5- Click OK44Specifying External Storage (2/5)The other method is to use the tree specifications.A dialog box is displayedThe new path appears in the features tree1- Double click on the path you want to modify2- Select a new path3- Click OK45Specifying External Storage (3/5)Each new computation will generate files. A new file will replace the corresponding old one. Before launching a new computation you may clear the “Computation Data” and / or the “Results” if you want it to supersede the previous one.The following data structure is created in the external storage directories :1- Click the “Clear Storage” icon2- Select the action you wantComputation filesResult files46To calculate, the computer needs a temporary storage location which is cleaned up when the associated analysis session is closed.Specifying External Storage (4/5)With this option you can indicate the data storage location.1- Click this icon2- Click ”Modify” to select a new directory3- Select a new path4-5- Validate with OK47Specifying External Storage (5/5) Analysis storage creationq CATAnalysisResults and CATAnalysisComputations files are created : The first time the computation is launched If the user explicitly define their locationq An analysis document which contains only specifications can be stored without links to Analysis storage.q These files are not seen anymore in partners applications that does not need them. Analysis storage readq Data are copied only when computation or post-processing need to access it.q There is a significant time reduction of Computed Analysis Document loading.q There is no more useless data reading (ex : read a computed document, modify the mesh, and re-computing). Analysis storage deletionq CATAnalysisResults and CATAnalysisComputations can be deleted manualy (equivalent to Clear capability).New R948 1- Click the Compute icon.3.2. Computing (1/4)Once you have successfully defined Restraints and Loads in your Static Analysis Case, you can undertake the actual results computation of that case.2- Activate the All (default) option.Upon successful completion of the computation the status of all objects in the analysis features tree is changed to valid.The Compute dialog box is displayed.Activate “Preview” if you want an estimation of the computation time.A series of status messages (Meshing, Factorization, Solution) informs you about the progress of the computing process.3- Click OK (or Yes) to launch the computation.49You can edit the default values of the Computation parameters of a Case Solution as follows :Computing (2/4)1- Double-click the Solution objects set in the analysis features tree to display the Computation Definition dialog box.For the gradient method two additional parameters must be specified2- Activate the method you want to apply.50There are four different solving methods for a static analysis :Computing (3/4)1- Auto method : One of the three methods below is automatically computed.2- Gauss method : Direct method.3- Gradient method : Solving iterative method which is memory saving but not CPU time saving.4- Gauss R6 method : Fast Gauss method.For any analysis method.Recommended for computing small/medium models.Recommended for computing huge models. Two additional parameters must be specified : maximum iteration number and accuracy factor.Recommended for computing large size models (default method).511- Duplicate CATIA Installation icon.Computing (4/4)While CATIA computes your analysis, the interactive mode is not available. So, you may launch a batch which performs the computation.4- As a result, when you launch the batch, a panel appears in which you will enter the name of the file to be updated as well as the name of the model to be computed.2- Rename the duplicated icon ( for example, CNextBatch).3- Edit the CNextBatch file and at the end of the file, replace start “CNEXT.exe -env %GenericEnvName%“ with the following: start “CNEXT.exe -env %GenericEnvName% -batch -e CATAnalysisBatch”.52In this lesson, you will learn about the Post-Processing capabilities of GPS and about performing a Refined Static Analysis.Image CreationImages LayoutResults ManagementOther CapabilitiesHistoric of ComputationParabolic Element TypeGlobal and Local Mesh RefinementMesh AdaptativityKnowledgeware for Analysis 4. Static Results Visualization and Refinement53Deformed Mesh images are used to visualize the finite element model in its deflected configuration, as a result of the environmental action (loading).4.1. Image Creation - Deformations 1- Click the Deformation icon. The Deformed Mesh image is displayed and a Deformed Mesh Image object appears in the feature tree under the active Static Case Solution objects set.If you de-activate this button you get the initial,i.e. undeformed, mesh.You can also set a shrink coefficient for all the elements of your mesh.2- To customize the visualization, double-click the Deformed Mesh Image object in the feature tree to edit the image. The “Image Fem Editor” dialog box is displayed.You can choose to see just one entity.54Von Mises Stress images are used to visualize Von Mises stress field patterns, which represent a scalar field quantity obtained from the volume distortion energy density and used to assess the state of stress.1- Click the “Von Mises iconThe Von Mises stress distribution on the part is visualized in iso-value mode, along with a color palette, and a Stress Von Mises Image object appears in the feature tree.Image Creation - Von Mises Stress 2- To customize the visualization, double-click the Von Mises Stress Image object in the feature tree to edit the image. The “Image Editor” dialog box is displayed.If you de-activate this toggle button the Von Mises stress image is displayed on the undeformed mesh.For a sound structural design, the maximum value of the Von Mises stress is generally considered to be less than the material yield stress value.55Displacement images are used to visualize displacement field patterns, which represent a vector field quantity equal to the variation of position vectors of material particles.The displacement resulting from part loading is necessary for a correct evaluation of the way in which the part behaves.1- Click the “Displacements” icon The Displacements distribution on the part is visualized in arrow symbol mode, along with a color palette.Image Creation - Displacements If you de-activate this button the Displacements image is displayed on the undeformed mesh.You can choose between a symbolic view (vectors) or an average-iso view (colors), and filter the desired displacement vectors components.2- To customize the visualization, double-click the Displacements Image object in the feature tree to edit the image. The “Image Editor” dialog box is displayed.561- Click the “Principal Stress“ iconStress Principal Value images are used to visualize principal stress field patterns, which represent a tensor field quantity used to measure the state of stress and to determine the load path on the part.At each node, the principal stress tensor shows the directions along which the part is in a state of pure tension/compression and the corresponding tensile/compressive stresses.The Principal Values Stress Tensor distribution on the part is visualized in symbol mode, along with a color palette : at each point, a set of three directions is represented by line symbols (principal directions of stress). Arrow directions (inwards / outwards) indicate the sign of the principal stress. The color code provides quantitative information.Image Creation - Principal StressesIf you de-activate this button the Principal Stress image is displayed on the undeformed mesh.You can choose between a symbolic view or discontinuous-iso view (colors), and filter the desired principal stress tensors components.2- To customize the visualization, double-click the Principal Stress Image object in the feature tree to edit the image. The “Image Editor” dialog box is displayed.571- Click the “Precision” icon Estimated Error images are used to visualize computation error maps, and evaluate the validity of the computation. It displays a predicted energy error norm map which gives qualitative insight about the error distribution on the part.The Estimated Error distribution on the part is visualized in fringe pattern mode, along with a color palette.Image Creation - PrecisionIf you activate this button the precision image is displayed on the deformed mesh.2- To customize the visualization, double-click the precision Image object in the feature tree to edit the image. The “Image Editor” dialog box is displayed.58Image Creation - Switching from one Image to AnotherWhen you create several images, the last created one is active. Here are two different ways to switch to a previously created image.2- You can activate and de-activate images with a right mouse click (key 3) in the features tree or directly on the image display.1- Click on the icon of an image you have already created. This will have the effect of making that image active, if you didnt modify its default parameters : otherwise a new one will be created.594.2. Images LayoutGenerated images corresponding to several analysis results are superimposed. If the global image cannot be properly visualized, you can tile these superimposed images into as many layout images in the 3D view.The images appear as superimposed2- Click Images Layout iconImages can be detached from each other 3- Select the direction along which you will tile the images.1- In the tree, activate the images you want to see.601- Select the image(s) you want to display.2- Click the “Image Animation” icon in the “Analysis Tools” toolbar.You can set the Number of frames parameter up to its maximum value (20) by pressing the Up combo. This gives you a smoother animation. It is also slower.4.3. Results Management - Image AnimationImage Animation is a continuous display of a sequence of frames obtained from a given image. Each frame represents the result displayed with a different amplitude. Running the frames sequence gives a feeling of motion.The image(s) is(are) animated with default animation parameters and the Animation dialog box is displayed.You can select which Play Mode you want.611- Select images and click the “Cut Plane” iconin the bottom toolbar. The Cut Plane Analysis dialog box is displayed.2- You can handle the compass with the mouse to rotate or translate the Cutting Plane, and visualize an internal image field.Results Management - Cut Plane AnalysisCut Plane Analysis consists in visualizing results in a plane section through the structure.By dynamically changing the location and orientation of the cutting plane, you can rapidly analyze the results inside the system.The compass is automatically positioned on the part.Before selectionning “Cut Plane” icon, you can put the compass on the face you want the plane to be at first.62Amplitude Modulation consists in scaling the maximum displacement amplitude for visualizing a deformed mesh image.You can either choose a large scaling coefficient to zoom on the deflected geometry or a small coefficient to obtain a more realistic visualization.The Amplitude Modulation function is useful for superimposed images to have the same amplitude modulation.1- Select an image and display it on the deformed geometry2- Click the “Amplitude Modulation” icon in the bottom toolbarResults Management - Amplitude ModulationThe Deform Window dialog box is displayed3- You can now change the magnification in three different ways :- Using the cursor.- Setting the “Deformed Coefficient” value.- Setting the “Maximum Displacement” value.You can reinitialized the coefficient631- Select an image (typically Von Mises Stress).2- Click the Extrema Detection icon in the “Analysis Tools” toolbarResults Management - Extrema DetectionExtrema Detection consists in localizing points where a results field is maximum or minimum.You can ask the program to detect both absolute extrema and an arbitrary number of local extrema for your field.The Image Extremum Create dialog box is displayed3- Enter the number of absolute and/or local extrema ( = identical values ) to detect. 4- Click OKThe extrema values are indicated on the image and in the tree64For example with , the informations are :1- Visualize a results image of your analysis solution2- Select an Image result in the tree.Click the Image Information iconA specific Image Information box is displayed.Results Management - Image InformationFor each image that you visualize, you have access to a specific Image Information box.This is particularly useful for the Von Mises and Precision images, for it is the only way to know the yield strengh of the materials in the part, and the global precision of your analysis.With , the informations are :651- Click the Report icon in the “Analysis Report” toolbar. An HTML file containing the Report of the Static Case Solution objects set computation is displayed.Results Management - ReportingA Report is a summary of an objects set computation results and status messages, saved in an editable file.The Reporting Options dialog box is displayedPressing the button on the right gives you access to your file system for defining a path for the output Report file. You can edit the title of the report.3- Click OK2- Choose an analysis case from the list66When an image is displayed, you can get relevant local information by draging the mouse cursor over elements or symbols.Node and element numbersDisplacement vector componentsVon Mises values on nodesEstimated energy error for each element4.4. Other Capabilities - Dynamic Query on Mesh67You can edit the number of colors, and imposed the values over which the color will be red, and under which it will be blueThe color repartition will be determined either by values over the entire model, or by values only on boundaryOther Capabilities - Customizing the Color PaletteFor images coming with a color palette, editing the palette enables the user to emphasize on particular values spread on the parts.The palette dialog box is displayed.1- Double click on the Palette to edit it684.5. Historic of ComputationYou can have an historic of the number of elements, nodes, etc. from the first computation to the last.3- Click the “Historic of Computation” icon in the Analysis Result toolbar.2- Make one or several successive computations1- Create the Sensors you want to keep track of (see Slide 67)The historic graph is displayed69To improve the precision of your analysis results, the first step is to increase the number of degrees of your elements, and compute with parabolic TE10 elements instead of the linear TE4 elements.TE10 parabolic elements have 10 nodes each, whereas TE4 linear elements only have 4 nodes. With parabolic elements, unknown field inside the element is interpolated with 2nd order polynomials.Two methods exist to change the element type.The mesh specifications box is displayedThe element type specification box is displayed.4.6. Parabolic Element Type3- Activate Parabolic2- Activate Parabolic1- Double click either on the mesh specifications symbol or on the corresponding feature in the analysis tree. OrClick on the “Element Type” icon in the “Mesh Specification” toolbar, for a global switching from TE4 to TE10 elements.70The mesh specifications box is displayed.4.7. Global and Local Mesh Refinement - Global SpecificationsThe second step when you want to improve the precision of your analysis results is to refine the mesh of your part. You can refine both the Size of a mesh, and the Sag (chord error). This can be performed both globally or locally.The mesh size is the dimension of the element edge and the sag is a measure of how closely the element boundaries follow the geometrical support. The smaller the mesh size and sag, the more accurate your analysis results will be.2- Reduce the global size and/or sag.1- Click either on the mesh specifications symbol or on the corresponding feature in the analysis tree.3- Click OKReal boundaryMeshSagSize71For the sake of efficiency, you can specify mesh size and sag locally (for example on one of the models faces).The mesh specifications box is displayed.A local mesh specification symbol is displayed, as well as a feature in the analysis tree.Global and Local Mesh Refinement - Local Specifications2- Select support and enter mesh value (for that you can use the dedicated tool).1- Click either on a local specifications symbol in the mesh specifications toolbar, or add a mesh specification from the mesh specifications box.3- Click OK72A powerful tool of GPS is the possibility to refine a given mesh only in areas of interest.You specify the areas where you want refinement to be managed with the so called Adaptativity Boxes.2- Click the first Adaptivity Box icon.A cuboid symbol representing the Adaptivity Box is displayed on the part.1- Perform a static analysis and compute a Static Case Solution4.8. Mesh Adaptativity : Creating Adaptivity Boxes (1/2)The Local Adaptivity Box dialog box is displayed, and current local error inside the box is indicated.3- Select existing Static Case Solution and specify target percentage error in Objective Error box.4- Click OKClick to centralize the box on the extremum73You can modify the box location with the compass (3 translations and 3 rotations).As you modify the Adaptivity Box, the corresponding local error % value displayed in the Local Error field is dynamically updated. An Adaptivity Box object appears in the features tree under the active Adaptivities objects set.You can modify the box dimensions by dragging one of its 14 control points.You can create several Adaptivity Box objects associated to the same Static Solution and involving different areas of the part.Mesh Adaptativity - Creating Adaptivity Boxes (2/2)742- Click on “Adapt button” in the Compute toolbar.The adaptative computation is then launched.1- Create “Adaptativity boxes” in an existing Static Case SolutionMesh Adaptativity - Managing AdaptivityAdaptivity Management consists of setting global adaptivity specifications and computing adaptive solutions.The “Adaptivity Convergence” box is displayed.5- Check results to see if your target error has been reached.3- Specify the maximum number of iterations. 4- Click OKAn “Adaptivity Convergence object appear in the tree 751- Perform static analysis and compute Static Case Solution.3- Click the first Adaptivity Box icon. Mesh Adaptativity - Selecting Image ExtremaYou can create adaptativity boxes in such a way that they are initially centered at image extrema locations.5- Click on Select Extremum button.The adaptativity box is automatically centered on the selected extremum.2- Create extrema points of your image (typically Mises or Precision).6- Select global or local extremum in tree.4- Specify Solution and Objective Error76The powerful knowledgeware infrastructure associated to the analysis workbench allows to establish rules and generate checks with the Analysis Sensors.The Analysis Sensors allow to extract informations from results and to keep those informations available through Knowledgeware processing.Once you have successfully completed a Static Analysis Results computation, you can create sensors to edit the parameter value.Energy Sensor is created by default at the first computation.3- In the tree, double-click on the sensor Maximum Displacement to edit the value or right click on Maximum Displacement and select Maximun Displacement Object.4.9. Knowledgeware for Analysis - Sensor Creating1- Right click in the tree on Sensors.1 function and select Create Sensor2- Click on dispmaxYou have to create as many sensors as you need to use in the Knowledge Advisor.77Visualization parameters setting in ”Options” from the Tools menuAccessing the knowlegde Advisor product from the Start MenuKnowledgeware for Analysis- Knowledge Advisor Product One of knowledge use is to create rules and generate checks which are relations that can only be created with Knowledge Advisor product.78A rule is a list of actions to be performed after the analysis is performed, using all available parameters (from the geometrical model and analysis results)1- Click on Rule iconMessage generated by the rule The rule is generated in the tree Knowledgeware for Analysis - Rule Creating2- Example of a conditional rule3- Select an Analysis sensor in the tree for the condition4- Write a rule79A Check is a set of relations to be verified in order to inform the user depending on its violation1- Click on Check icon Knowledgeware for Analysis - Check Creating (1/2)4- Select an Analysis sensor5- Select the constraint 3- Write the message2- Select Type of check80Type of message generated by the check In the tree, checks inform the user in case of violation of the relation or notRelation isnt violatedRelation is violatedKnowledgeware for Analysis - Check Creating (2/2)81Rule which isnt updatedTwo solutions exist to update relations : Knowledgeware for Analysis - UpdatingRules and Checks are automatically updated by a full computation (Compute All). Otherwise, a specific updating is necessary, as follows :In the Tree, Right Click on Relations, then select “Relations object” and “Measure Update”In the Tree, Double-click on Relations to access Knowlegde Advisor and select “measure Update” icon from the menu82In this lesson, you will learn about virtual parts. The Various Transmission Types ListExamples Showing Various Transmission TypesApplying Actions to Virtual PartsShare a handler point of Virtual Parts5. Virtual Parts83Smooth Virtual Parts softly transmit their actions : they dont stiffen the deformable body.Contact Virtual Parts softly transmit their actions while preventing from body inter-penetration.Rigid Virtual Parts stiffly transmit their actions : they locally stiffen the deformable body.Rigid Spring Virtual Parts stiffly transmit their actions and behave like a 6-dof spring .Smooth Spring Virtual Parts softly transmit their actions and behave like a 6-dof spring .5.1. The Various Transmission Types ListVirtual Parts are structures created without a geometric support. They are used to transmit action at a distance.Virtual Parts transmit actions (masses, restraints and loads) applied at the handler point, to the geometries to which they are attached.The handler point is either user-specified, or automatically defined as the centroid of the targeted geometry.Each Virtual Part type transmits its action to the real Part to which it is attached in a specific way.845.2. Examples Showing Various Transmission TypesRigid Virtual PartSmooth Virtual PartFVirtual PartClamp855.3. Example of Rigid Spring Virtual Parts useWe want to analyze only the alternator support. The goal is to avoid meshing all the engine block where the alternator support is fixed, using Rigid Spring Virtual Parts (on which we can define stiffness data)Cylinders blockAlternator supportFixations3. Analyze the alternator support : the clamped areas are as stiffened as if we had analyzed the engine cover. So, the results are more representative. 2. Enter the equivalent stiffness for the three fixations (from experimental measures or from cylinders block analyze applying unit forces with stiffness=1/displacement).1. Apply three Rigid Spring Virtual Parts, and clamp them.86There are four types of restraints that you can apply to a virtual parts handler point : - Ball joints- Pivots - Sliders- Sliding Pivots1- Click on one of the technological restraints3- Define an axis (except for ball joints)5.4. Applying Actions to Virtual Parts - RestraintsThe restraint will automatically be applied to its handler point4- Click OK2- Select the Virtual Part. 87You can apply two types of loads on a Virtual Part :- A distributed force- A distributed momentJust select a Virtual Part as support for the distributed force or momentApplying Actions to Virtual Parts - Loads88If you have to transmit forces with virtual parts on several surfaces, you must :In the case of a single part, create a single virtual part and select your surfaces.In the case of an assembly of parts, create a virtual part for each part selecting the corresponding surface. Each virtual part will share its handler point. Only one node is generated when virtual parts are sharing the same handler point.2. Select the shared GSD point.Repeat for the others virtual parts1. Select a faceOnly one single node generated5.5. Virtual Parts sharing a single handler pointNew R989In this lesson, you will learn how to perform a Modal Analysis on a Single Part, especially how to define Restraints and Mass Equipment on the part, and compute the Analysis.Creating Additional Mass EquipmentUnrestrained or Restrained PartComputing the Analysis6. Dynamic Pre-Processing and Computation90Ensure that part has material defined thenOpen Modal Analysis Work BenchGeneral Process for a Dynamic AnalysisApply Restraints to the modelApply additional masses to the model (optional)Create ImagesPerform ComputationSelect a Dynamic ModeAnalyze the Results and Refine if necessary911- Click the Distributed Mass icon. Symbol representing the distributed mass is visualized (here on a crankshaft).A Distributed Mass object appears in the features tree under the active Masses objects set.6.1. Creating Additional Mass Equipment - Distributed MassDistributed Masses represent scalar point mass fields equivalent to a total mass concentrated at a given point, distributed on a virtual part or on a geometric support.The user specifies the total mass. This quantity remains constant independently of the geometrical support. The point where the total mass is concentrated is the centroid of the selected geometry, or the handler of the virtual part.The Distributed Mass dialog box is displayed. The distributed mass replace a component with a mass judged important for the analysis.2- Select the support (a virtual part or a geometry). 3- Enter the value of the total mass. 4- Click OK92Creating Additional Mass Equipment - Mass DensitiesLine (Surface) Mass Densities represent scalar line (surface) mass density fields of given intensity, applied to curve (surface) geometries. The user specifies mass density. The total mass then depends on the geometry selection.1- Select support(s)(an edge)2- Specify mass density93The Free Modes Dynamic Analysis Case is ready to be computed.6.2. Unrestrained or Restrained Part - Free ModesRestraints are optional for Modal Analysis computations. If not created, the program will compute vibration modes for the free, unrestrained part.The “Frequency Analysis” case contains by default an empty restraints set as well as an empty loads set.For a free modes computation there must not be any restraints defined in the frequency analysis case. You must choose “Free Frequency Analysis” when starting the Analysis Workbench or insert a new frequency case with no restraints defined.Open Analysis Workbench with “Free Frequency Analysis”.94There are three available restraints for frequency analyses on real parts.You can use :- Clamps- Surface Sliders- Advanced RestraintsYou have seen before how to create these Restraints in the Static Analysis.Unrestrained or Restrained Part - Restrained Modes95 1- Click the “Compute” icon. Upon successful completion of the computation, the status of all objects in the analysis features tree is changed to valid.6.3. Computing the Analysis - ComputationYou compute a Frequency Case the same way you compute a Static Case. Check that the External Storage location gives enough free space.The Update dialog box is displayed. Activate “Check Update Time” if you want an estimation of the computation time.A series of status messages (Meshing, Factorization, Frequency Computation) informs you about the advancement of the computation process. 3- Click OK to launch the computation.2- Activate the All (default) option. 96Computing the Analysis - Editing Computation ParametersYou can edit the default values of the Computation Parameters of a Case Solution the following way :You may select the solving method : Gauss (default, through inverse subspace iterations) or Lanczos (more appropriate for large models 100,000 dof s)You can also tune the maximum iteration number and accuracy parameters.1- Double-click the Solution objects set in the analysis features tree to display the Computation Definition dialog box.2- Specify the number of modes you want to compute.97In this lesson, you will learn about the Modal Post-Processing capabilities of GPS.Image Creation Results Management7. Dynamic Results Visualization98Once you have successfully completed a frequency case computation, you can create four types of images :- Deformations- DisplacementsThese images are created in the same way as in a static analysis. The only difference is that you have as many separate images as there are dynamic modes.7.1. Image Creation99Click the Deformation icon. The Deformed Mesh image is displayed and a Deformed Mesh Image object appears in the feature tree under the active Static Case Solution objects set.Image Creation - Visualizing DeformationsDeformed Mesh images are used to visualize the finite element mesh in the deformed configuration of the system, as a result of environmental action (loading).1001- Double-click the image object in the feature tree to edit it.2- Select the desired Dynamic ModeImage Creation - Selecting a Dynamic ModeOnce they are created you can edit the displacements, stress or deformations images to select the dynamic mode you wish to visualize.There are by default ten dynamic modes available. You can have more by editing the computation parameters as seen earlier on.The Image Editor dialog box is displayed.3- Click OK101As for a static case, you have some tools to help you analyze resulting images.Animation is very useful for modal analyzes :- Image AnimationThe tools we presented in the static analysis are also available here. 7.2. Results Management102To Sum UpIn this course you have seen :How to perform a Static Stress AnalysisHow to perform a Dynamic Modal Analysis103Some tests has been made so as to know which element to use as the case may be.TE4 and TE10 comparisonStatic AnalysisFrequency AnalysisBuckling Analysis8. Elements tests with ELFINI solver1048.1. TE4 and TE10 comparisonLet see the 3D elements differences in terms of accuracy and convergence. 30mm mesh size max: 1.36 mmq Linear TE4 elements have a very slow convergence compare to Parabolic TE10 elements.q For larger mesh sizes, TE4 elements give erroneous results. 30mm mesh size max: 0.505 mm 14mm mesh size max: 0.766 mm 7mm mesh size max: 1.16 mmTE4 TE107mm mesh size max: 1.38 mm 14mm mesh size max: 1.38 mm 3mm mesh size max: 1.27 mm1058.2. Static AnalysisThree main points are tested here : cylindrical shells, plate with distortion, and torsion. q We notice that T6 and Q4 elements converge to the theoretical value for a 15X15 mesh.q We note that Q4 elements are quite bad with intensive distortion (80 deg), but under 60deg, all the elements are good.q In this case, 3D TE4 elements are quite bad, especially with important twisting, like T3 elements. The others are very corrects.1068.3. Frequency AnalysisTwo kinds of free vibrations are discussed : with cylindrical and plate shells. q Notice that only Q4 element has a bad behaviour from the 6th mode. Under this mode, all the three kinds of elements have the same accuracy. q Q4 element begins to have a bad behaviour from the 12th mode. Under this mode, the accuracy is good.1078.4. Buckling AnalysisA test of shell elements with out-of-plane buckling has been performedq We notice that only T3 elements are bad for this case, and T6 and Q4 have an excellent accuracy.108Frequently Asked Questions (1/3)sWhat is the reasonable accuracy for an analysisqA good global precision is around 4 and 5 %. However, precision may be less than 10% in critical areas, and superior to 10% in low stress level areas.sWhat is the difference between a global and a local errorqGlobal error is about all the structure, whereas local error depends on global rate and is about an area of the structure.sIs it possible to apply an un-uniform force loadqYes, with the Data Mapping function (see in pressure load help).sHow can I know if my results are correctsqSee the global error and verify if the residus in the equilibrium equations from the ficel file tend towards 0.sIs it possible to combine two static setqLinear combination of static cases is now possible, with the Combined case functionnality. You have to select the static cases and affect them coefficients.109sWhat happened when a hole with boundary restraints is killedq Thanks to the integration CAD-CAE, the CATAnalysis will automatically be flagged as not “up to date”. A message like “The analysis specification XX is not applied on a support” appears. That constraint has to be deleted manually.sCan we apply a pressure on a holeq Yes, with the Bearing Load function. We can automatically apply distributed pressures on holes (see Help).sCan I add new material characteristics to the material catalogq yes, in editing the Catalog.CATMaterial file, after having de-activate the read only option. You can create families of materials (alu alloys,) and new materials (Alu 6061,). Frequently Asked Questions (2/3)110sMust I keep computational data in external storageq Computational data contain results from solving like the rigidity matrix and others information. If you need them for future analysis, do not delete them, they can keep you from wasting time.Frequently Asked Questions (3/3)New R9sCan I apply pre-processing on a surface part of a solidq Yes, using the Sewing Part design functionnality.1.Create a sketch in GSD on the solid surface.2.Click on the Create Datum option. Click on the GSD Split function. Select the surface and the sketch. Choose the Keep both side option.3.Go in part Design : click on the Sew Surface function. Select one of the two splited surfaces. De-select the Topology Simplification option. Put the OpenBody in NoShow.4.Go in GPS : surfaces are pickable and you can apply pre-processing features.111