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CATIA Training

COPYRIGHT DASSAULT SYSTEMES Version 5 Release 19 September 2008 EDU-CAT-EN-GAS-FS-V5R19

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Generative Assembly Structural Analysis Detailed Steps

COPYRIGHT DASSAULT SYSTEMES 2

TTaabbllee ooff CCoonntteennttss Recap Exercises ..................................................................................................................................... 3�

1. Face Face Connections Property Recap Exercise ......................................................................... 3�2. Distant Connections Recap Exercise ............................................................................................ 11�

Master Exercise: Static Analysis on an Assembly ................................................................................ 19�1. Pre-Processing .............................................................................................................................. 19�2. Computation .................................................................................................................................. 41�3. Results Visualization ..................................................................................................................... 44�4. Publishing Report .......................................................................................................................... 51�

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Recap Exercises

1. Face Face Connections Property Recap Exercise

Load CATGAS_FootPeg_Recap.CATProduct

• Click on the “Slider Connection” icon • Select the correct assembly constraint

• Click on Ok

Here is what you should obtain:

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• Click on the “Contact Connection” icon • Select the correct assembly constraint

• Click on Ok

Below is what you should obtain:

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• Click on the “Fastened Connection” icon Select the correct assembly constraint

• Click on the “Clamp” icon • Select the back surface of the peg mount

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• Click on Ok • Apply surface slider on cylindrical surface of foot peg. Click on surface slider Select the inner cylindrical face of peg

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You will get :

Below is what you should finally obtain:

• Click on the “Distributed Force” icon

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• Select the top face of the peg mount

• Apply a force of 3000N in the –z direction • Click on ok

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• Double-click on the green tetrahedron

• Check “Parabolic” • Click on Ok • (Do it for both parts)

• Check the consistency of the model by checking on • Check if the connections are Ok

• Click on Ok

• Compute the analysis. Click the “Compute” icon • You will receive following warning during computation

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• Click OK on the warning.

• Click Yes on Computation Resources Estimation dialog box.

• Click the “Von Mises Stress” icon • You will get the following image

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2. Distant Connections Recap Exercise

Load CATGAS_Tank_Assembly_Recap.CATProdcut Switch to "Generative Structural Analysis" workbench

2.1 - Defining a Contact Connection:

• Click on the "Contact" Connection icon

• Select the "Surface Contact" assembly constraint as support • Click on Ok

Defining the Virtual Bolt tightening connection:

• Click on the "Virtual Bolt Tightening "connection icon

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• Select "coincidence constraint" as support • Enter the Tightening Force of 5000N • Click on Ok. • Repeat this operation for each hole

2.2 - Applying a Pressure:

• Click on the "Pressure" icon

• Select all the internal surfaces of the assembly "tank + cover" • Apply a pressure of 500Pa. • Click on Ok.

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Note: For the computation, it is necessary to clamp a part of the assembly, i.e. the bottom of the tank.

2.3 - Computation

• Click on the "Computation" icon

• Click on Ok

• Click on the "Displacement" icon • Double-click on "translational displacement vector" in the specification tree

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• The "Image edition" dialog box appears: Select "Average-ISO" and click on Ok

You obtain:

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• Change the "deformation scale factor" for a better visualization

• Click on the “Precision” icon.

• Click on the "Image Extrema" icon • Ask for 4 "Local Maxima extrema" detection:

• Click on Ok You should get this in the tree:

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You notice that the maximal errors are at the connections between the tank and the cover. Consequently it is necessary to refine the mesh around these places. Before you refine the mesh, you will define 4 groups, snapped on the 4 Local Extrema.

• Click on the "Box "Group icon

• Click on the "Select an Extremum" button • Select the fist "Local Maximum" in the tree

• Click on "Inactive box" and resize the box • Click on Ok. • Repeat this operation for the 3 next extrema. • In case where group is not get created at connections between the tank and the cover,

manually created the box group, which will capture the nodes at connection showing high error values.

2.4 - Refining Locally the Mesh for improving accuracy

You will now define "Adaptivity" where the local errors are maximal.

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• Click on the "Global Adaptivity" icon

• Select the "Mesh Part" as support: • Enter "10%" as objective error • Click on Ok

• Compute the analysis with Adaptivity

• Now you will define 4 "local adaptivity"

• In the tree, right-click on "Global Adaptivity"

• Click on "Local Adaptivity"

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This dialog box appears:

• Select as support one of the "Box" groups you have define above

• Enter an objective error of 5% • Define 3 others "Local adaptivity" using the 3 others groups

• Compute using "adaptivity" Use 3 iterations.

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Master Exercise: Static Analysis on an Assembly

1. Pre-Processing

Load the CATIA document “Assembly.CATProduct”

• Open the Assembly.CATPoduct

The assembly is opened in the Assembly Design Workbench.

1.1 - Material Properties

Go to Custom View Modes and check Material option

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You must obtain:

1.2 - Analysis Connections

• Open the GPS Workbench and define a Static Analysis

• Select Static Analysis and click on OK.

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At this step, you should have something like this:

You are working on an assembly and not an isolated part. Consequently, all the parts must be connected to each other and you must pay attention to restrain the correct degree of freedom (D.O.F)

1.3 - Contact connection between the plate and the platen_link

To be able to define the contact connection, you must have either an assembly or an analysis constraint as support. In your case, you will use the Assembly Contact connection previously defined.

• Click on the Contact Connection icon in the Connection toolbar

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• Select the contact assembly connection that links the two parts together:

You get this:

• click on Ok

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1.4 - The Screws

The titanium screws are used to tighten the plate and the platen_link together. To modelize such connection (Bolt tightening), you need previously to some analysis constraints between the screws and the plate.

• Click on the “General Analysis Connection” icon

• Click on the top face of the plate

• As second component, select the bottom face of the screw

• Click on OK.

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You obtain:

1.5 - Define another “General Analysis Connection” on the second screw

You should obtain:

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Now you have defined 2 “General Analysis” connections, you will use them as support to define a contact connection.

Click on the Contact Connection icon in the Connection toolbar

• Select one of the general connection • Click on Ok • Repeat this operation for the second general connection. You obtain:

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So far, you have defined contact connections in order to prevent the screw from going trough the plate. Now, you have to prevent the plate from sliding in the horizontal plan. Consequently, you will have to define some other general and contact connections.


• Select this surface as first component:

• Select as second component the inner hole surface of the plate:

• Click on Ok • You should obtain:

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• Define another “General Analysis” connection on the second screw

Now you have defined the 2 needed general analysis connection, you will apply 2 contact connections on them

• Click on the Contact Connection icon in the Connection toolbar

• Select one of the general analysis connections as support. • Click on Ok • Repeat this operation on the second general analysis connection • Here is how your assembly should look like:

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Now that you have restraint the D.O.F of the plate and the screw, you can define the bolt tightening connection

• Click on the “ Bolt tightening” connection icon

• Select as support the assembly coincident constraints

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• Key a tightening force of 300N • Check the screw orientation. It must be like this:

• Click on Ok • Repeat this operation on the other coincidence constraint of the 2nd screw (pay attention to

the screw orientation) • You must obtain:

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You are now done with the screws. You will now fix the shaft on the plate using “virtual Bolt tightening” connection As above, besides of the virtual bolt tightening, you will have to define some general/contact analysis connection to restraint enough the D.O.F of the shaft You will now define a contact connection to prevent the shaft from going trough the plate

1.6 - Define a general analysis connection between the top surface of the plate and the bottom surface of the shaft:


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• Select the plate top surface as first component

• Select the shaft bottom surface as 2nd component:

• Click on Ok

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• Here is what you obtain:

Now you have defined the general analysis connection, you will apply a contact connection on it

• Click on the “Contact connection” icon

• Select as support the previously created general analysis connection

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• Click on Ok

It is time now to define the virtual bolt tightening

• Click on the “Virtual Bolt tightening” icon

• Select the coincidence assembly constraint as support

• Key 400N as tightening force

• Click on Ok

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• Repeat this operation for the 2 other holes

• At the end, you should get:

You are now done with the connections between the parts. The 2nd step consist in restraining the platen_link

1.7 - Restraints

• Click on the slider connection icon

• Select the holes inner surfaces:

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• Click on Ok

You will now restrain the X direction

• Click on

• Select the platen_link bottom surface

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• Un-check all the restrains except the “translation 1”:

• Click on Ok

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1.8 - Load

You will apply a bearing load

• Click on

• Select these 3 surfaces as support:

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• Key –100N in the “Z” field • Angle: 350deg. • Orientation: Parallel • Profile type : Sinusoidal • Distrbution : Outward

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• Click on Ok

If you get this, you are done with the Master_exercise_Step_1:

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2. Computation

Load the previous CATIA Document "Master_Exercise_Step2" First of all you have to specify an External Storage location. 1.

• Click on Temporary Data Location icon in the Storage Location toolbar. • Select a directory with enough space to make the computation.

• In the features tree, double-click on the Computations link and define a directory where the

computation files will be saved

• Select a path and click on OK to validate.

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• In the specification tree, double-click on the Results link and define a directory where the results files will be saved

• Select a path and click on OK to validate.

2.

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At this step, you have defined the different storage locations. Now, you can compute your analysis 3.

• Click on the Compute icon The Compute dialog box appears:

• Select the "All" option.

• Click on OK.

Wait while computing

Here is what you should obtain:

At this step, you computed successfully the analysis. The step (3) will consist in visualizing the results.

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3. Results Visualization

3.1 - Display the Von Mises Stress

Before you begin, hide all the connections, load, restraints.

1. Click on the Von Mises Stress icon

• Double-click on the Color Map

• Key 20 as number as colors

• Check the “imposed max” option • Impose 4e6

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• Click on Ok You obtain:

3.2 - Von Mises Selection

• Double-click on

The dialog box appears:

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• Click on “Selections” tab

• Select these mesh-part:

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• Click on the down arrow button to push selected items in Activated group as shown

• Click on ok You obtain:

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3.3 - Von Mises Cutting plane

• Click on

• Drag the cutting plane using the compass • Un-check “show cutting plane”

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• Click on Close

4.

3.4 - Image Animation

• Click on the “Amplification Magnitude” icon

• Key 2.5 as scaling Factor • Click on Ok

• Click on the “Animate” icon

• Key 20 as number of steps • By clicking the “More” you can access more options.

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• Click on Ok where you are done • See step3_end.CATAnalysis for reference.

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4. Publishing Report

Load the previous CATIA Document or the "Master_Exercise_Step4" file

4.1 - Define a Customized Report

• Click on the "advanced report" icon

• Define the Output directory and give a title to the report • Click on Ok

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• Double-click on "nodes and elements"

• Select "Make Description"

• Add to report by clicking on the vertical bar • Expand "Static Case Solution.1"

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• Select "Stress Von Mises", "Deformed Mesh" and the "Translational displacement"

• Add to report by clicking on the vertical bar

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• Click on Ok

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