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Generative Part Stress Analysis
Preface What's new ?
Getting Started Basic Tasks Workbench
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Preface CATIA - Generative Part Structural Analysis and Generative Assembly Structural Analysis Version 5 Release 3 allows you to quickly perform first order mechanical analysis for 3D parts. This application is intended for the casual user. Indeed, its intuitive interface offers the possibility to obtain mechanical behavior information with very few interactions. The dialog boxes are self explanatory and require practically no methodology, all defining steps being commutative.
As a scalable product, CATIA - Generative Part Structural Analysis Version 5 Release 3 can be cooperatively used with other current or future companion CATIA Version 5 products such as CATIA - Part Design, CATIA - Assembly Design and CATIA - Generative Drafting. The widest application portfolio in the industry is also accessible through interoperability with CATIA Solutions Version 4 to enable support of the full product development process from initial concept to product in operation.
The product CATIA - Generative Assembly Structural Analysis has been designed as a very useful extension to CATIA - Generative Part Structural Analysis enabling the mechanical behavior study of a whole assembly.This product is fully integrated in Generative Part Structural Analysis product and has been conceived with the same "easy to learn" and "fun to use" ergonomy creating then a very powerful tool.
The CATIA - Generative Part Structural Analysis andthe CATIA - Generative Assembly Structural Analysis User's Guides have been designed to show you how to analyze a part or an assembly operating within a specified environment. There are several ways of subjecting a part to external actions. There are also several types of useful output information. This book aims at illustrating these various possibilities.
Using This Guide This book is intended for the user who needs to quickly become familiar with CATIA - Generative Part Structural Analysis and CATIA - Generative Assembly Structural Analysis Version 5 Release 3. The user should be familiar with basic CATIA Version 5 concepts such as document windows, standard and view toolbars.
To get the most out of this guide, we suggest you start reading and performing the step-by-step tutorial "Getting Started". This tutorial will show you how to analyze a part from scratch.
The next sections present the main capabilities, in the form of basic user's tasks. It may be a good idea to take a look at the section describing the menus and toolbars.
Where to Find More Information Prior to reading this book, we recommend that you read the CATIA Version 5 Infrastructure User's Guide.
CATIA - Part Design User's Guide and CATIA - Assembly Design User's Guide may also prove useful.
What's new ? CATIA Version 5 Release 3 presents new functionalities for CATIA - Generative Part Structural Analysis product:
The Adaptivity functionality enables local mesh refinements respecting a Precision Goal. After two computations, the Convergence of parameters as the Maximum of von Mises stresses for example can be studied through a Function Editor. The mesh Sag and Size specifications ergonomy has been enhanced. A Dynamic display enables the user to visualize mesh or nodes local values resulting from a computation. The Color Palette customization functionalities have been improved. The Wireframe Visualization Mode for ISO-Values has been developed.
Getting Started Before getting into the detailed instructions for using CATIA - Generative Part Structural Analysis andCATIA - Generative Assembly Structural Analysis Version 5 Release 3, the following tutorial aims at giving you a feel of what you can do with the product. It provides a step-by-step scenario showing you how to use key functionalities. The main tasks described in this section are:
Tasks Entering the Stress Analysis Workbench and Selecting a Part Creating Restraints Creating a Force Creating a Slider Connection Computing a Stress Analysis Computing a Normal Modes Analysis Viewing Displacements
These tasks should take about 20 minutes to complete.
Entering the Stress Analysis Workbench and Selecting a Part
This first task will show you how to enter the Stress Analysis workbench and load a part.
Before starting this scenario, you should be familiar with the basic commands common to all workbenches. These are described in the CATIA Version 5 Release 3 Infrastructure User's Guide. You can use the Rod_For_Analysis.CATPart document from the SAMPLES/gps_analysis directory for this task. 1. Select File -> Open then select the desired .CATPart file. This opens a Part Design document containing the selected part. 2. Select the part in the feature tree.
3. Click the Apply Material icon . The Material library appears.
4. Select a material family. Select the desired material from the displayed list then. Click OK.
The material is applied. You can visualize the material properties and its analysis characteristics by selecting the material in the feature tree and using Edit -> Properties -> Analysis. 5. Select File -> New then select Analysis from the List of Types.
An empty document and the Analysis toolbar are displayed. 6. Select Window -> Tile Horizontally.
To have a easy access to the part to load.
7. Click the Select Part icon .
8. Click the Part in the Part Design document.
The part is then loaded in the Stress Analysis workbench.
If you select Start->Analysis & Simulation -> Stress Analysis from a CATPart document containing the part without any material, the material library will appear directly for an easy material selection.
You can use command Start->Analysis & Simulation -> Stress Analysis from a CATPart document instead of steps 5 to 8.
Creating Restraints This task will show you how to create slider and clamp restraints on a part.
1. Click the Slider icon .
The Slider dialog box appears.
2. Select a geometry (an edge ( Reference axis only ) or a surface : any other geometry you can highlight with the cursor).
Several axis systems are also displayed on the geometry to symbolize the anticipated result. Green axes represent free translation directions while blue axes represent fixed translation directions.
3. Activate the degrees of freedom on which you want to impose a restraint. Specify the value of each imposed displacement, expressing all of them in local or global coordinates. (The local axis system: cartesian, circular or revolute corresponds to the geometry you have selected).
4. If you need to create more sliders, select other geometrical entities to create the restraint.
The dialog box is still displayed and you can create other sliders by repeating the previous steps.
5. Click OK to create the Slider. 6. Click the Clamp icon
. The Clamp dialog box appears.
7. Select the cylindrical geometry as shown.
8. Click OK to create the restraint.
The final restraints on your part are as shown.
Creating a Force This task will show you how to create a Force.
1. Click the Force icon . The Force dialog box appears.
2. Select a geometry.
Several arrows previewing the anticipated result are displayed.
3. Set the values of each force component according to the axis system you have chosen.The arrows are refreshed once new values are entered.
For a CATIA - P2 interface, you can select the compass to impose the direction of the arrows: Drag the compass by handling the red square and drop it on the appropriate surface.The normal (perpendicular) direction to this surface defines the new direction.Then, click on the Compass Direction button to take this new direction into account.You can now invert the direction if desired, editing the values of the three components. Please refer to the CATIA Infrastructure User's Guide for further information. 4. Click OK.
The Force is created.
Creating a Slider Connection This task will show you how to create a Slider Connection between two parts.
This task is independent from the previous ones. You must own the Generative Assembly Structural Analysis product to follow this scenario.
You can use the Rod_For_Analysis.CATPart and the Rod_Axis_For_Analysis.CATPart documents from the SAMPLES/gps_analysis directory for this task. 1. Select "Product 1" ( in the feature tree of the product document ) then select Insert -> Existing Component. ( If a product document is not yet opened, execute File -> New and select Product in the type list ). 2. Select the first Part : Rod_For_Analysis.CATPart. 3. Repeat Steps 1 and 2 for the second Part : Rod_Axis_For_Analysis.CATPart . You can use the Copy and Paste or Copy and Paste-Special method to insert a part from a Part Design document to a Product one.For further information please refer to the CATIA Assembly Design User's Guide.
4. You must now apply a material on each Part:
-Select Product1 then select Edit -> Design Mode.
5. Expand the feature tree to access to the part's body of the first part.
-Double-click on it to edit it. The Part Design Toolbar appears.
-Select the "Apply Material" Icon and choose one of the presented materials.
If you use the Functionality Start->Modal or Stress Analysis from a document including a part without any material, the Material Library appears and you can select one of them to apply it on the part before entering the Analysis workbench.Therefore you do not have to enter the Part Design workshop for such an operation. 6. Repeat Step 5 to apply a material on the second part . 7. Double-click on "Product1" in the feature tree to come back to the Assembly Design workshop.
8.Select the "Contact Constraint" icon. 9. Select the outer surface of the cylinder and the corresponding inner surface of the rod.
10.Click OK to validate.
11.Select Start->Analysis Simulation ->Stress Analysis to enter the Stress Analysis workbench.
12. Select the "Parts Connection" icon.
-The Connection Panel appears.
13.Select Face to face and Slider connection options in the combo boxes. 14. Select the constraint symbol which links the parts. 15.Click OK.
16. The Slider Connection is created.
-A symbol representing this particular connection is created.The Assembly is then designed.
Be sure to fixe all the global degrees of freedom of your assembly otherwise a global singularity will be raised at computation ( such a model is insolvable).To correct easily the model, the induced motion of the assembly will be simulated and visualized after computation. The CATProduct and the CATAnalysis files are now associated: If you modify the CATProduct and you save the CATAnalysis file, the CATProduct file will be saved as well. Once all restraints and loads are set on the Assembly, you can launch a computation as defined in the previous tasks : Computing a Stress Analysis or Computing a Normal Modes Analysis.
Computing a Stress Analysis
This task will show you how to compute a stress analysis and to visualize von Mises stresses results. You must have performed the first three tasks prior to beginning this task.
1. Click the Compute
icon . The Compute dialog box appears.
A Status message indicates if the program is ready for computation.
Otherwise a missing element would be declared (at least one restraint, for example).
2. Click OK to compute and display the resulting stresses.
3. Click the Wireframe
icon in the general toolbar.
The von Mises results are visualized with curves which represent the different thresholds.
Computing a Normal Modes Analysis A Normal Modes Analysis computation corresponds to a sequence of operations resulting in the computation of dynamic mode shapes and vibration frequencies of the part. This task shows how to run a normal modes computation on a specified part.
You must use the Dynamics Analysis workbench to perform this task.
The part material, additional masses (if any) and restraints (if any) need to be specified prior to the computation. Note that:
not specifying a restraint has the effect of generating free body vibration modes. not specifying additional mass distributions has the effect of generating vibration modes under the effect of the part's structural mass only.
You can use the Rod_For_Analysis.CATPart document from the SAMPLES/gps_analysis directory for this task.
1. Click the Compute icon .
The Compute dialog box is displayed.
2. The overall Mesh Sag and Mesh SIze features are created in the features tree.
3. Click on Cancel in the Compute panel to edit later on those features.
4. By default their values are convenient for a rough computation ( with a linear interpolation). However you can modify them to set more appropriate values: Double click on the Mesh Size symbol
in the features tree.
The Mesh Size dialog box appears
5. Set an overall adequate value.
6. Click Ok. 7. Repeat steps 4 to 6 with the Mesh Sag symbol
in the features tree.
8. Click the Compute icon .
The Compute dialog box is displayed.
9. Click More to enlarge the panel: you can modify the computation parameters such as the Number of Modes if you wish.
10. Click OK to run the computation. The status of the computation is displayed on the Status line
11.The results are displayed.
12.You can select a normal mode in the presented list and animate it.
This task will show you how to visualize Displacements after a computation.
You must have successfully performed a Stress Computation prior to beginning this task.
1. Click the Displacement icon . The Displacement dialog box appears.
Leave the Display Arrow box unchecked.
An ISO-value of the part displacement field magnitude is displayed.
The Palette dialog box enables you to modify the color distribution to focus on specific values.
For this functionality refer to the task Editing the Color Palette,
2. You can visualize the part inner displacements using the Cutting Plane: select the corresponding checkbox (CATIA - P2 interface and licence only ).
You can handle the compass with the mouse in order to rotate or translate the Cutting Plane.( To do so, select an edge of the compass and drag the mouse ).
3. Click OK to exit this view.