ADM740_WorkshopsWS10_Flex Tutorial

1、WORKSHOP 10 FLEX TUTORIAL,Flex Tutorial,In this workshop, you swap a rigid lower control arm with a flexible control arm in a suspension template. First, you need to change the memory for A/View and A/Solver to be huge. Windows: Start Menu Programs MSC.Software MD ADAMS ADAMS Settings Adams Solver a

2、nd Adams View Preferences MemSize = Huge Unix: Right Click Adams Toolbar Start Registry Editor - Adams Solver and Adams View Preferences MemSize = Huge Note: You need to start a new A/Car session after this change. Also, be sure to make the changes in both the Adams Solver and Adams View preferences

3、 folders.,Opening a subsystem To open a subsystem: From the File menu, select Open. Right-click the Subsystem Name text box, point to Search, and then select subsystems.tbl. Double-click TR_Front_suspension.sub. Select OK.,Flex Tutorial,Flex Tutorial,To create the flexible lower control arm: From th

4、e Adjust menu, point to General Parts, point to Rigid-to-Flex. In the Current Part Name text box, select gel_lower_control_arm. In the Modal Neutral File text boxes, point to the files LCA_left_shl.mnf, located in the database.,In the main window, Adams/Car displays the flexible bodies on top of the

5、 rigid bodies. You can see bodies in this configuration when the model is displayed in wireframe mode. Tip: Press Shift + S with the graphics area selected to toggle between wireframe and shaded mode.,Flex Tutorial,Identify the attachments: On the Status bar of the main menu, right-click the Informa

6、tion tool stack, and then select the Model Topology by Parts tool. The Information window displays the topology map. Scroll to the top of the Information window and find gel_lower_control_arm, the associated list of attachments, and their corresponding parts.,Flex Tutorial,PICTURE,Associate connecti

7、ons to flexible body using Preserve Expression Select the Connections tab in the Rigid/Flex Swap window Select the Move tab to highlight all connections. Next select Preserve expression. Click Apply and repeat the process for the right control arm.,Flex Tutorial,A warning message appears to indicate

8、 that the flexible body can not be resized simply by moving the hardpoints any more.,Flex Tutorial,To run an analysis with your suspension with flexible control arm: Save the subsystem as TR_Front_Suspension_flex to the acar_training database. Create the assembly From the File menu, point to New, an

9、d then select Full-Vehicle Assembly. Fill in the dialog box as shown next, and then select OK. Click on the folder icon in Front Susp Subsystem field, to use the present subsystem in memory for the full vehicle model.,Flex Tutorial,Changing Modal Content By default, when you integrate an MNF into an

10、 Adams/Car template, Adams/Flex enables all the modes that were defined during the FEM modeling except the probable rigid body modes. It is important to have the right modal content in flexible bodies, because an MNF has more modes than are needed to simulate a particular response. To increase the e

11、fficiency of the simulations, you could disable any modes that do not contribute to the motion that your flexible part will undergo during the simulation. Be careful when disabling modes, because a disabled mode corresponds to a constraint to the part. Changing the modal content of a flexible body c

12、orresponds to a flexible body setup. In addition, sometimes, it is not possible to know the contribution of one particular mode to the overall deformation of the flexible body.,Flex Tutorial,You can manually toggle modes on or off. This gives you greater flexibility and helps you avoid potential pro

13、blems. You can enable and disable modes in several ways: Individually, based on their mode number. As a group, based on their mode number or frequency. Through a table editor. The table editor also lets you define displacement and velocity initial conditions associated with every mode. Based on thei

14、r strain energy contribution, but you can only do this after a successful analysis. For more information on this technique, see the Adams/Flex online help.,Flex Tutorial,To disable individual modes: Some of the modes of the flexible lower control arms do not contribute effectively to the dynamic beh

15、avior of the entire system. We recommend that you disable them to reduce the computational effort and to improve the efficiency of the simulation. You must disable these modes for both the left and the right side because a left and a right MNF defines the flexible lower control arms. Zoom in on the

16、front suspension. Right click the gel_lower_control_arm_flex, point to Modify, and then select modify icon . The Flexible Body Modify dialog box appears.,Select Modal ICs. The Modify Modal ICs dialog box appears. Hold down the Shift key, select modes 28 and 29, and then select Disable Highlighted Mo

17、des. Close the Modify Modal ICs dialog box. Repeat Steps 2 through 6, for the right lower control arm, ger_lower_control_arm_flex. (You could also just right-click the Flexible Body text box, point to Flexible Body , point to Pick, and from the screen select ger_lower_control_arm_flex.) Close the Fl

18、exible Body Modify dialog box.,Flex Tutorial,Performing a Full-Vehicle Analysis You are now ready to perform the full-vehicle analysis. After you perform the analysis, you can change the inertia modeling of the flexible body to compare the effect of the modal flexibility on the dynamics of the vehic

19、le. To perform the full-vehicle analysis: From the Simulate menu, point to Full-Vehicle Analysis, point to Open-Loop Steering Events, and then select Step Steer. Set up the analysis as follows: Full-Vehicle Assembly: fveh_assy Output Prefix: tst End Time: 4,Flex Tutorial,Number of Steps: 400 Initial

20、 Velocity: 70 (take the default of km/hr) Gear Position: 3 Final Steer Value: -45 Step Start Time: 1 Duration of Step: 1 Steering Input: Angle Keep the defaults for Cruise Control (off) and Quasi-Static Straight Line Setup (on). Select Apply, so the dialog box stays open for the analysis you will ru

21、n in the next section. The SDI test rig applies to the assembly the inputs you specified and performs a dynamic analysis.,Flex Tutorial,To change the inertia modeling: Right click the gel_lower_control_arm_flex, point to Modify, and then select modify icon to bring up the Flexible Body Modify dialog box. Set Inertia modeling to Rigid body. Select OK. Close the Modify Flexible Body dialog box. Submit another step steer analysis usi