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1、Crankslider Mechanism Tutorial Problem Statement The purpose of this exercise is to use the IntelliMotion Builder to demonstrate the procedure for configuring the mechanism and to then check for interference. The mechanism comprises of a crank connected via link1 and a universal joint (cardan compon
2、ent) to the Arm component to provide an oscillatory motion. This in turn is connected via another link to a collar that slides back and forth on a shaft. Link2 Collar Crank Arm Link1 Cardan Step 1 Open Model & Set Workbench You will need to run the DDMV5R7 or DDMV5R8 profile shortcut to enable the D
3、ynamic Designer Workbench. Open the product file crankslider_tutorial.CATProduct located in the crankslider sub-folder in the tutorials directory of the installation. If your workbench is not already set to Dynamic Designer (look at the Workbench icon at the top right hand side of the toolbar), then
4、 activate the Dynamic Designer Workbench under START DIGITAL_MOCKUP DYNAMIC DESIGNER. The Dynamic Designer commands can be accessed via the toolbar icons or the pull down menu (see below) Step 2 Create Mechanism from Assembly To auto create the mechanism from the assembly, click on the Convert Mecha
5、nism Icon . This will bring up a dialog box asking if you want to convert the assembly constraints when the mechanism is created. Make sure this option is selected before proceeding. The Screen should now look like that below where there are motion entity icons on the graphics screen. Expand the tre
6、eview to show the APPLICATIONS DYNAMIC DESIGNER branches. You should see the following mechanism data: Note that the assembly constraints have been mapped to Dynamic Designer joints and that the grounded parts in the assembly have been automatically made grounded in Dynamic Designer. Step 2 Default
7、Simulation Settings The Dynamic Designer Settings can be accessed from two locations. Global settings can be found in the Catia OPTIONS dialog (TOOLS OPTIONS menu selection) These setting are applied to future mechanisms in different assemblies. We will not be changing these for this exercise, but t
8、his is useful to be aware of. Model specific settings can be found by expanding the APPLICATIONS BRANCH of the Catia Treeview, and under the Dynamic Designer Branch, right clicking on the MOTION MODEL branch and selecting the PROPERTIES option. This option can only be done once a mechanism has been
9、started (i.e. a moving or ground part exist). You can also access mechanism settings from the MOTION MECHANISM settings. We need to change the direction of gravity to match the orientation the model was built in. In this case gravity must act in the X axis direction. To change this, click on the dir
10、ection pull down list and select the Standard X option. STEP 3 Define Motion The complete mechanism is not designed to operate under gravity, so we need to provide input motion representing a motor connected to the system. Because the joints define how the parts move with respect to one another, we
11、apply motion to the joints as it is clear in which directions the parts can move. To drive the crankslider, we are going to put a motion on the cylindrical joint connecting the Crank to the Crank Housing. In the image shown below, this is joint 4. Please expand the branch under the joint to verify t
12、he joint selected is the correct one. Do add a motion, double click on this joint (i.e. Joint.4 in above images) in either the treeview or in the graphics window. Change the MOTION ON from TRANSLATE Z to ROTATE Z Change the MOTION TYPE from FREE to VELOCITY Specify a CONSTANT velocity of 360 DEG/SEC
13、 Make sure you click on the RED tick to accept the value change. Press OK to accept the motion definition. You should now see an arrow on the joint in the graphics window. STEP 4 Run Simulation We are ready to run the simulation. From the MOTION menu select the SIMULATE option to set the simulation
14、settings and to run the solver. Alternatively, you can click on the toolbar icon. Leave the simulation time at 1 seconds and the number of frames at 60. Click on the START button to run the simulations. Once the simulation completes, the analysis dialog will close automatically. STEP 5 Review Animat
15、ion We can now review the results. As part of the simulation, a replay object is automatically generated. You can view the replay by expanding the REPLAY branch at the bottom of the treeview, or by clicking on the toolbar icon. Once the Replay dialog appears, you can review the motion and do all the
16、 standard option available in replay like save the animation to file, add an interference analysis, or check for clearances. STEP 6 Interference Detection Interference checking is done using the DMU utilities in Catia. The first step is to define a DMU Clash Analysis. From the MOTION menu, select th
17、e CLASH option. This will bring up the DMU Check Clash dialog. Leave Clash Type as Contact + Clash, but change the selection option to Between Two Selections. Select LINK1 for the Selection1, change focus to Selection 2 and select the ARM component Press OK to accept and keep this. Arm Selection 2 L
18、ink1 Selection 1 To run the analysis, display the REPLAY object . You can view the replay by expanding the REPLAY branch at the bottom of the treeview, or by clicking on the toolbar icon. Click on the EDIT ANALYSIS option Click on the ADD button to add an analysis to the replay object. Select the In
19、terference.1 analysis to add and press OK. Press OK again to complete adding analyses. On the Replay dialog, change the Interference option from OFF to ON. Press the PLAY button to replay the motion and check for interference while animating (You may notice the parts highlighting while this is happe
20、ning. This means that clash exists between the parts at that result frame). Once the animation has finished, you will find a new branch under the Replay object called Interference Results.1. You can Double click on this object to review the interference results. NOTE: In some versions of Catia, the
21、interference is not being detected where the lugs are cutting into the side of the arm, even though these parts are highlighted while the analysis is being done. STEP 10 Change Geometry and Re-simulate To correct the problem, we need to change the geometry of the arm. We will place fillets on the ve
22、rtical edges of the arm between the two lugs. Double click on the arm to go into part edit mode. From the toolbar select the Edge Fillet icon. Specify a Fillet radius of 0.375 inches (or 9.525 mm) Pick on the 2 vertical edges shown below (you will see the proposed face edges in pink) Press OK to accept the fillets. The geometry should now look like: Return to the Dynamic Designer Workbench by double clicking on the PRODUCT level of the treeview. Repeat the interference check and you should now find that no interference occurs. This concludes the tutorial