WORKSHOP 14 KNOWLEDGEWARE CAT509, Workshop 14, March 2002 WS14-1

Problem Description WORKSHOP 14 The preliminary design of the ATV Foot Peg must be completed as soon as possible and must meet the given structural requirements. The design must not exceed the material yield strength under loading and it must not deform in a manner causing interference with other parts of the vehicle. An initial static analysis of the Foot Peg has been completed (Workshop 2). To assist in our design iterations, we need to activate CATIA Knowledgeware capabilities to provide immediate feedback on the critical analysis parameters.

Suggested Exercise Steps WORKSHOP 14 Suggested Exercise Steps Open the existing document for the Foot Peg static analysis. Create analysis sensors for maximum displacement and maximum stress. Create a knowledge rule for maximum displacement. Create a knowledge check for maximum stress. Modify the Foot Peg design to meet requirements. Compute the analysis for the modified design. View results.

Step 1. Open the analysis document Open the Foot Peg static analysis document from the training directory. Steps: 1. Select File and Open… from the top pull-down menu. 2. Access the class workshop directory using the typical Windows interface. 3. Open the ws14footpegstatic.CATAnalysis document by double-clicking. The document is opened in the GSA workbench. 1 2 3

Step 2. Create analysis sensors Analysis sensors must be created to provide results information to the Knowledgeware application. Create a sensor for maximum displacement and for maximum stress. Steps: 1. Right mouse click on Sensors.1 in the specification tree. 2. Click on Create Sensor in the menu. 3. Highlight dispmax (max. displacement) in the sensor creation window. 4. Click OK. 5. Repeat steps 1-4 to create the misesmax sensor (max. Von Mises stress). 1 5 3 4 2

Step 2. Create analysis sensors The sensors branch in the specification tree must be expanded to view the newly created sensors. Steps: 1. Click the plus (+) symbol on the branch node to expand the sensors branch. 2. Expanded branch shows all sensors. The Energy sensor is automatically created with every analysis document. It measures global strain energy of the structure. Default Energy sensor 1 “dispmax” sensor 2 “misesmax” sensor

Step 3. Create knowledge rule Activate the ability to view knowledge rules and checks in the analysis specification tree. Steps: 1. Select Options from the Tools menu. 2. Select Analysis & Simulation branch. 3. Select General tab. 4. Activate both boxes to show parameters and relations. 1 2 4 Update the analysis solution if needed. Steps: 1. Check for “update needed” symbol on the Static Case Solution.1 2. Compute to update the analysis results (see Section 3). Symbols shows update needed

Step 3. Create knowledge rule 1 Now create a rule that will monitor maximum displacement of the Foot Peg and provide pop-up messaging on the screen. Rules are created using the CATIA Knowledge Advisor. Steps: 1. Select Start from the top pull-down menu. 2. Drag the cursor and click the Knowledge Advisor workbench under Infrastructure. 2

Step 3. Create knowledge rule 2 The Knowledge Advisor workbench should now be active . Steps: 1. Click the Rule icon from the Knowledge Advisor workbench. 2. Key “Displacement Max” as the name of the rule. 3. Key in a description for the rule or accept the default. 4. The rule will be saved under the Relations category – do not modify. 5. Click OK. 6. Rule Editor window displays the active rule (Displacement Max). 3 1 4 5 6 Rule definition entered here Dictionary categories to assist in defining rules

Step 3. Create knowledge rule 1st line: Rule description Define the rule. Steps: 1. Click to place the cursor at the end of the 1st line and then hit the Enter key to start a new line. 2. Select Keywords in the Dictionary window. 3. Double-click on “if” to begin the line. 4. Single-click the Max Displacement sensor in the tree to list its parameters in the Members of All area. 5. Double-click on ‘Maximum displacement Value’ to add it to the definition. 6. The parameter for the max. displacement value is added. 7. The current value is shown (.011 in). 1 2 3 4 5 6 7

Step 3. Create knowledge rule Define the rule (cont.). Steps: 8. Key in the remainder of the rule definition as shown. Dictionary selection can be used for Keywords, Operators, Messages, etc. 9. Click OK when finished. 10. If successful, the rule message will be displayed. Note: The current max. displacement value exceeds our defined rule value of .009 in. The message suggests a design modification is required. 11. Click OK to dismiss the message. 8 9 Rule created 10 11

Step 4. Create knowledge check Create a check that will monitor maximum Von Mises stress on the Foot Peg so that our design does not exceed the material yield strength. Steps: 1. Click the Check icon from the Knowledge Advisor workbench. 2. Key “Von Mises Max” as the name of the check. 3. Key in a description for the check or accept the default. 4. The check will be saved under the Relations category – do not modify. 5. Click OK. 6. Check Editor window is displayed. 2 3 1 4 5 6

Step 4. Create knowledge check Define the check. Steps: 1. Select Warning as the check type. 2. Key warning message as shown. 3. Place the cursor at the end of the 1st line and then hit the Enter key to start a new line. 4. Single-click the Max Von Mises sensor in the tree to list its associated parameters. 5. Double-click on ‘Maximum Von Mises Value’ to add it to the definition. 6. The parameter for the max. Von Mises value is added and the current value is shown (3484.577 psi). 7. Enter the less than symbol (<) as shown. 1 2 1st line: Rule description 3 5 4 7 6

Step 4. Create knowledge check Define check (cont.). Steps: 8. Expand the tree to view the Foot Peg. 9. Single-click the Foot Peg to list associated parameters. 10. Scroll to locate Pressure in Members of Parameters area. 11. Click Pressure to display parameters including material yield strength. 12. Double-click on ‘Aluminum…Yield Strength’ to add to the definition. 13. Click OK when finished. Note: The check is showing green which means the max. Von Mises stress is below the material yield strength for Aluminum. 8 10 9 11 12 Check created and shows green light (check not violated) 13

Step 5. Modify Foot Peg design 2 The knowledgeware results indicate the maximum Von Mises stress is acceptable, however the maximum displacement of the Foot Peg is too large. Let’s modify the Foot Peg design as suggested by the knowledge rule to reduce maximum displacement. Steps: 1. Double-click the PartBody in the tree to switch to the Part Design workbench. 2. Part Design is now the active workbench. 3. Expand the PartBody branch to show solid features. 1 3

Step 5. Modify Foot Peg design Now in Part Design, reduce the length of the Foot Peg by modifying the corresponding solid feature. Steps: 1. Double-click Pad.1 in the tree to modify. Pad Definition window is displayed. 2. Double-click the parameter Offset.19 to modify its value. 3. Change the value to 7 inches as shown in the Constraint Definition window. 4. Click OK. 5. Click OK in the Pad Definition window. The length of the Foot Peg is reduced to 7 inches. 2 1 2 5 4 3

Step 5. Modify Foot Peg design Preview of modified spacing After making the change, it is apparent that the outer edge is too thin. Modify the spacing between the top face cutouts. Steps: 1. Double-click the feature pattern (RectPattern.1) in the tree to modify. 2. Select the First Direction tab. 3. Key in a new spacing for the First Direction of 2.5 inches. 4. Click the Preview button to view change. 5. Click OK to accept. The cutouts are now positioned closer together. Arrow shows 1st direction 2 1 3 4 5

Step 6. Compute analysis 1 Symbol showing analysis case not updated 2 Now that the Foot Peg design has changed, our analysis conditions have changed as well. The analysis must be computed again. Steps: 1. Return to the GSA workbench by double-clicking the Finite Element Model branch in the tree. 2. Select the Compute icon. 3. Specify that All parameters should be used in the calculation. 4. Click OK. Symbol showing analysis case not updated 2 3 4

Step 7. View results 1 3 Max. displacement is now acceptable 2 Immediately after computing the analysis solution we can verify our rule and check. In this case our design modifications are successful. Steps: 1. A message generated from the knowledge rule pops onto the screen after the computation is complete. 2. The check for max. Von Mises stress is green indicating the value is less than the material yield strength. 3. The value of each sensor can be seen by double-clicking on the sensor in the tree. 1 3 Max. displacement is now acceptable 2