1. WORKSHOP 11 SUSPENSION SYSTEM I

3. Workshop Objective Software Version Files Required
Inspect the toe angle that the wheel exhibits throughout its vertical travel of 80 mm in jounce and rebound.
Software Version
Adams 2013
Files Required
Use file suspension_parts_start.cmd.
Imported from suspension_parts_start.cmd.

4. Problem description
The given model is a geometric representation of a short-long arm (SLA) suspension subsystem.
The steering_rack and body_ground are constrained as shown in the following figure:
A translational joint connects the steering_rack to the body_ground.
A fixed joint connects the body_ground to ground.
You will use construction points in this workshop.
Explain construction points, and how to use them.
You will not create any, but you will reference existing construction points while building joints.
Construction points are named HP1, HP2, and so on. HP stands for hardpoint.
Demo the Table Editor and show the students how to access the hardpoint locations.

5. The lower_arm and lower_strut are constrained as shown next:
A spherical joint connects the lower_strut to the lower_control_arm.
A revolute joint connects the lower_arm to the body_ground.

6. The upper_arm and upper_strut are constrained as shown next:
A revolute joint connects the upper_arm to the body_ground.
A hooke joint connects the upper_strut to the body_ground.

7. Suggested Steps Open the model. Inspect the model.
Constrain the suspension subsystem model.
Apply motion to the model.
Verify, simulate and save the model
Perform optional tasks.

8. Step 1. Import Model To start the workshop:
Select Existing Model and start Adams/View from the directory exercise_dir/mod_11_suspension_1.
Open the model command file suspension_parts_start.cmd.
This file contains commands to build a model named suspension and the following parts with geometric representation:
Illustrate jounce and rebound on the board, so the students know what result they should be looking for.

9. Step 2. Inspect the Model b c d
In this section, you’ll investigate the model to note its movement and topology, especially that of the part tie_rod.To inspect the model:
Simulate the model, noting the movement of tie_rod.
From the Tools menu, select Database Navigator.
Set the pull-down menu at the top of the Database Navigator to Graphical Topology.
Double-click suspension, and then select tie_rod. c b d

10. Step 3. Constrain the Suspension Subsystem Model
Reference Page Constrain the tie rod as shown next:

11. Step 3. Constrain the Suspension Subsystem Model (Cont.)
To constrain the model with a spherical joint:
Select the 2 Bod-1 Loc option, Normal to Grid
First body: Spindle_Wheel
Second body: tie_rod
Set the location to HP8
Note: HP8 belongs to ground. We are simply referencing its location for the creation of the new markers (I and J) that represent the joint. a

12. Step 3. Constrain the Suspension Subsystem Model (Cont.)
Use the Hooke joint tool to create a hooke joint:
Select the 2 Bod-1 Loc option, Pick Feature
First body: tie_rod
Second body: steering_rack
Set the location to HP7
Set the first direction from vector HP7 to HP8
Set the second direction from vector HP7 to HP13
Tip: When setting the direction, move your cursor in the direction of the ending vector (HP8 and HP13, respectively), until its name appears on the screen. When the name appears, left-click to select it.
Inspect the tie rod again, and notice the connection representations to the steering_rack and spindle_wheel.
Simulate the model. a a b

13. Step 4. Apply Motions a c b To apply motions:
At the marker .Spindle_Wheel.Center, apply a point motion in the Y direction of the Spindle_Wheel.Center.
Tip: Make sure Construction is set to 1 Location, Pick Feature.
Modify the motion to use the function, Displacement(time) = 80*sin(360d*time).
Modify the translational joint, rck_body_joint, between the steering_rack and the body_ground to be a fixed joint, so that the steering_rack is unable to translate during a simulation. b c

14. Step 5. Verify, Simulate and Save the Model
Verify and simulate the model
Now, to see the model’s full range of motion, verify and simulate the modulate simulate it:
Verify the model.
Run a one-second, 50-step simulation.
To save your work:
Save your model as suspension_parts.cmd.
If you want to further explore the model, as suggested in the next section, leave the model open. Otherwise, proceed with the next step.
Exit Adams/View. a b

15. Step 6. Optional Tasks To modify hardpoint locations:
From the Tools menu, select Table Editor.
From the options along the bottom of the Table Editor, select Points.
Change the Loc Y value of HP3 from to 400.
As you make this change, note how the upper arm’s connection to the spindle changes.

16. Step 6. Optional Tasks (Cont.)
Make scripts for different hardpoint configurations:
Open the Command Window (F3) and change a hardpoint location in the model.
Note the command that appeared when the hardpoint was modified. It should be something like:
point modify point_name=.suspension.ground.HP5 &
location=-305.0,12.75, relative_to=ground
Create a script that modifies several hardpoint locations and name it something like ‘config1.cmd’.
Use the F2 key to read config1.cmd into Adams/View: all hardpoint locations should update as per the settings in the file.
Note: see the example files config1.cmd, config2.cmd in the /completed directory for examples.

17. Workshop 11, Review
What is the difference between a point motion and a joint motion? ______________________________________________________________________________________________________