1. Workshop 12 atv – lower control arm

3. Workshop Objectives Software Version Files Required
Learn how to convert a rigid body into flexible body using ViewFlex.
Creating flexible body using Geometry method.
Software Version
Adams 2012
Files Required
mod_13_atv.cmd
Located in the directory exercise_dir/mod_13_ATV

4. Suggested Exercise Steps
Import the ATV model
Run a dynamic simulation and save the results
Creating flexible lower control arm
Flexible body attachment verification
Converting the flexible body into rigid body
Generating the flexible body with proper attachment
Animate the simulation results
Save your work
Optional Tasks

5. Step 1. Import File b f d c e To import a file Start Adams/View
Under the Welcome dialog box, select Existing Model.
Set the Working Directory as exercise_dir/mod_13_atv.
Click on the File Name file folder icon and select the file MOD_13_ATV.cmd.
Click OK
ATV model is now loaded in Adams/View, with model name MOD_13_ATV b f d c e

6. Step 2. Run a Dynamic Simulation and Save the Resultsb c e d
Run a simulation using the simulation script SIM_SCRIPT
Under the Simulation tab, click Run a Scripted Simulation in the Simulate Group
Select Scripted as the Simulation Type
Enter SIM_SCRIPT as the Simulation Script Name
Click Start Simulation
Save the Simulation Results as Rigid_LCA
Click OK a e f

7. Step 3. Creating Flexible Lower Control Arm
You now convert the rigid left Lower Control Arm into Flexible body using ViewFlex Feature.
Under the Bodies tab, click ViewFlex in the Flexible Bodies group
Right-click in the Part to be meshed field and select the left lower control arm RB2_left_lca_59
Make sure the Material is Steel
For the Number of Modes enter 10
Make sure the FlexBody Type selected is Geometry
For Element Specification select size
In the Element Size field enter 5mm
Check the Collapse Small Edge option
Click OK
The lower control arm is now automatically replaced with the flexible body. a b e g f h c d i

8. Step 4. Flexible Body Attachment Verification
In the previous step, you have created a flexible lower control, which automatically replace the rigid control arm. In the automatic method you need to verify if the flexible body is connected exactly the same way as that of the rigid part in the assembly.
Pull down View > Part only…
Under Selections, pick .MOD_13_ATV.RB2_left_lca_59.flex
Click OK a

9. Step 4. Flexible Body Attachment Verification (Cont.)
Now you could see only lower control arm flexible body in Adams graphics area. To know how the left lower control arm is connected to the frame, damper and knuckle, refer to the workshop 8. As shown in the images, ViewFlex created an attachment point with a spider web with four legs connected to the lower control arm and the center point for connecting to the rest of the system at respective location. Are all these attachments are correct? Will this work as expected ? In the next steps you will see how to create flexible body and create the attachment points manually, before replacing the rigid body.

10. Step 5. Converting the Flexible Body into Rigid Body
In this step you will convert the flexible body back to rigid body.
Pull down View > Model
Right click on the lower control arm in the graphics area
Click Make Rigid
In the make_rigid_panel set Retain mesh to no
Click OK b c d e

11. Step 6. Generating the Flexible Body With Proper Attachments
In this step you will create a flexible lower control arm with proper attachments. You need to create attachments manually. During attachments creation, you need select the locations for the “selection type geometries”, which are provided in the file Marker_ref.cmd
Pull down File > Import
Right click in the File To Read field and select Browse…
From the Select one file dialogue box, select the file Markers_ref.cmd
Click Open
Click OK c e d

12. Step 6. Generating the Flexible Body with Proper Attachments (Cont.)
Once you import the file in the ATV model, You could see the markers created on the ground as shown in the image.
Pull down View > Part Only …
From the Selection list, select .MOD_13_ATV.ground
Click OK
If nothing is displayed in the graphics area, press “CTL+V” key
MARKER_
MARKER_
MARKER_
MARKER_
MARKER_
MARKER_
MARKER_

13. Step 6. Generating the Flexible Body with Proper Attachments (Cont.)
Pull down View > Model…
To turn off the name visibility pull down Edit > Appearance.
In the Database Navigator select the model + MOD_13_ATV
Click OK
In the Edit Appearance dialogue box, set Name Visibility to Off d b e f

14. Step 6. Generating the Flexible Body with Proper Attachments (Cont.)
Right click on the left lower control arm Part:RB2_left_lca_59
Select Make Flexible
Select Create New
In the Number of Modes field enter 10
Select Advanced Settings b a c d e

15. Step 6. Generating the Flexible Body with Proper Attachments (Cont.)
Set Element Specification to Size
Set Element Size set 5mm
Check in Collapse Small Edge
Make sure the Material is Steel
For the Number of Modes enter 10
Select Attachments c d a b e f

16. Step 6. Generating the Flexible Body with Proper Attachments (Cont.)
Make sure the Message Window displays information about node and elements. In the graphics area, the rigid lower control arm is now overlapped with the nodes and elements.
Click the Find Attachment tab. The Attachment Points Definition Table is now appended with the 4 rows. Note that the markers are referenced from the ground part that you imported through file Markers_Ref.cmd
Click on the first row. Note that this refers to the location of the lca front bushing location BUSHING_1. As soon as you click the marker, it is selected and highlighted in the graphics area.
Select Cylindrical for Selection Type. Here you will select the nodes of the lower control arm that fall in the cylinder to be connected.
Select Rigid(RBE2) as the Attachment Method.
For Radius enter 8.0mm
Check in Symmetric a d b c e f g

17. Step 6. Generating the Flexible Body with Proper Attachments (Cont.)
In the following steps, you are going to select the two end points for the cylinder. Since you have selected the Symmetric option, the length of the cylinder will be double than the distance you select for the end points.
Right click in the End Location field and select Pick Location. From the graphics area select the marker .MOD_13_ATV.ground.MARKER_ As soon as you pick the marker it will become the first end point of the cylinder. You will notice a white circle at that location.
To select the second end point, Once again right click in the End Location field and select Pick Location. From the graphics area select the marker .MOD_13_ATV.ground.MARKER_ The cylinder will look like the image shown on right side

18. Step 6. Generating the Flexible Body with Proper Attachments (Cont.)
Click on Transfer id
You have now selected the nodes for the lower control arm front bush connection. Follow the same procedure for the lower control arm rear bush location.
The 2nd row in the Attachment Point Definition table corresponds to the lower control arm rear bush location. You need to use the following markers for defining the end locations of the cylinder
.MOD_13_ATV.ground.MARKER_
.MOD_13_ATV.ground.MARKER_
For the attachment creation at shock rod connection, follow the same procedure above with radius of the cylinder 5mm.
The 3rd row in the Attachment Point Definition table corresponds to the connection between lower control arm and shock rod. You need to use the following markers for defining the end locations of the cylinder
.MOD_13_ATV.ground.MARKER_
.MOD_13_ATV.ground.MARKER_ a

19. Step 6. Generating the Flexible Body with Proper Attachments (Cont.)
You will now select the nodes for attachment at the spherical joint at the left lower control arm and wheel joint.
Select the row 4 in the Attachment Point Definition Table
Select Spherical for Selection Type
In the Attachment Method select Rigid(RBE2)
In the Radius field enter 10mm
Click on Transfer IDs, which shows 72 nodes selected for attachment for the spherical joint.
Click OK b c d a e f

20. Step 6. Generating the Flexible Body with Proper Attachments (Cont.)
The flexible body created now with the proper attachments at the connection as shown in the images on right side.

21. Step 7. Run a Dynamic Simulation and Save the Resultsb c d
Now that the flexible body is created, you can run the simulation.
To run the simulation follow the procedure described in the step 2 and save the results as Flex_LCA
In the Adams PostProcessor you can now compare the bushing forces results in Rigid_LCA and Flex_LCA
From the Simulation list select the Rigid_LCA and Flex_LCA
From the Results Set select BUSHING_1
From the Component select FX
Click Add Curves

22. Step 8. Animate the Simulation Resultsb c
To load the animation in the Adams/PostProcessor:
Click on the Create a New Page icon
Right click in the plot area and select Load Animation
From the Database Navigator select Flex_LCA
Click the Play Animation button to animate the model and see how the lower control arm deforms during the animation. d

23. Step 9. Save Your Work To save your work Save the database.
Exit Adams/View

24. Step 10. Optional Task
Following are the optional tasks in this tutorial
Create the flexible lower control arm including the stress modes and recover the stresses using Adams/Durability

25. Workshop 12, Review Workshop Questions
What are the files generated during the ViewFlex mnf generation process?
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What happens to the rigid body CM marker, when the rigid body is converted into flexible body?
Is it possible to convert the flexible body back to rigid body?