Adams/CHASSIS INTERFACE WORKSHOP 2 Adams/CHASSIS INTERFACE

WORKSHOP 2 – Adams/CHASSIS INTERFACE Problem Statement Using several different example vehicle models, calculate and plot various suspension characteristics.

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) Model Description This workshop uses several different models from the example library included with Adams/Chassis installation. The following are among the types of models used: SLA Quadralink Central link

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) Creating a new fingerprint to calculate achassis_gs suspension characteristics Here you work with a fingerprint to plot and add events to an existing vehicle database. To create a new fingerprint: (Here it is assumed that you already have the achassis_gs_front_sys.xml opened) On the Main tools menu, click Test mode In the bookshelf view, expand Suspension Right-click Front Ride Motion to select Add Event to New Fingerprint Using Model. The Select Model for New Event window appears.

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) Select achassis_gs_front_sys, and then click OK. Adams/Chassis adds fingerprint_2 to the treeview. In the treeview, verify that the Front Ride Motion event (achassis_gs_front_sys_fride) is selected for fingerprint_2. In the property editor, set: Rise-to-curb to 0.0 Jounce travel to 80.0 Rebound travel to 80.0 If necessary, click to clear the Front Auto Alignment checkbox.

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) Do one of the following: On the Tools menu, click Test, and then click Build and Run Selected Events From the Main toolbar, click the Build and Run Selected Events Right-click treeview to select Build and Run Selected Events from the shortcut menu. The Adams/Chassis command window builds and runs your model. Close the command window.

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) Plotting the results On the Main tools menu, click Review mode In the treeview, select the Front Ride Motion event you just created. In the property editor, select Plots. Do one of the following: On the Tools menu, click Review, and the click Execute Selected Plots. From the Main toolbar, select the Execute Selected Plots Right-click the treeview, and then select Execute Selected Plots from the shortcut menu. NOTE: Adams/Chassis launches Adams/PostProcessor to display the plot. Use the plots to answer review Questions 1 and 2 at the end of this workshop. Close Adams/PostProcessor and all command windows. Return to the Build mode by selecting from the toolbar.

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) To copy an example database: On the Tools menu, click Utilities, and then click Database Utilities. Adams/Chassis displays the Database Utilities window. Select the Copy Database tab. Select the Find tool next to Database To Copy (.vdb). In the Select .vdb Directory to Copy window, select pickup_swb.vdb, and click OK. Click Copy Database to Working Directory on the Select .vdb Directory to Copy window Click OK Select Cancel to exit the Database Utilities window. Register the database as you did in Workshop 1. 

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) Analyzing the pickup model This particular model uses a twin I-beam front suspension with a Haltenberger steering subsystem and a Hotchkiss (solid axle with leaf spring) rear suspension. To analyze the pickup model: On the Main tools menu, click the Load Model button. In the Select File window, select pickup_swb.vdb for the Registered Database. Select pickup_swb_front_sys.xml, and then click Open. Switch to Test mode. In the bookshelf, right-click Front Displacement Roll Motion to select Add Event to Current Fingerprint Using Model. Select Model for New Event window appears.

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) In the Select Model for New Event window, select pickup_swb_front_sys, and then select OK. Set Rise-to-curb to 0.0 and Wheel travel to 80.0. On the Main tools menu, click Build and Run Selected Events Switch to Review mode. In the Review mode treeview, select pickup_swb_front_sys_frollid. Do one of the following: On the Tools menu, click Review, and the click Execute Selected Animations On the Main toolbar, click the Execute Selected Animations Right-click the treeview to select Execute Selected Animations from the shortcut menu. The animation is then loaded in Adams/PostProcessor.

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) Rotate the model using the Dynamic Rotate tool Notice the differences between this suspension and steering model and the achassis_gs model you examined earlier. On the Tools menu, click File, and then click Exit to return to Adams/Chassis. Plot the results from pickup_swb_front_sys_frolld only. Use the results to answer Question 3 at the end of this workshop.

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) Plotting roll camber coefficient versus roll angle In this section, you want to make a plot of camber coefficient versus roll angle. Since this plot is not automatically generated by Adams/Chassis for the Roll Motion event, you need to create the plot manually from the list of Suspension Design Module (SDM) requests. To find the request ID: On the Tools menu, click Help, and then click Adams/Chassis Help. The Adams/Chassis online help appears. On the Adams/chassis online help, click Adams/Chassis Build Mode. In the table of contents, expand Modeling, and then select Suspension Design Module.

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) In the SDM Requests chart, find the request ID for the front roll camber coefficient. This is the numerical ID given to the request statement in the .adm file that defines roll camber coefficient. Use this value to answer Question 4 at the end of this workshop. Now you can attempt to create the plot. Open Adams/PostProcessor On the Main tools menu, click Create a new page Toggle the dashboard visibility to On Find roll camber coefficient or its SDM request ID in the list of available requests. You will not be able to find it. Why you did not find plots for any of the SDM requests in the list? Because you run a roll motion event, not a ride motion event. In a roll motion event, SDM requests are optional. You can find more information in the SDM section of the Adams/Chassis online help.

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) To turn on SDM requests: Exit Adams/PostProcessor. Click Exit, don’t save Return to Adams/Chassis Build mode. Select pickup_swb_front_sys in the treeview. Select the Properties tab in the editor. Expand the system _parameters menu. Expand the optional_requests menu and then select sdm_output Change the value of this parameter to 1. This turns on SDM requests. Select Apply to use SDM requests during this session. Return to Test mode.

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) Solving using Adams/Solver Since the SDM requests were missing from the previous .adm file, you need to generate a new .adm file and solve it using Adams/Solver before you can plot the requests. To create the new .adm file: From the treeview, select pickup_swb_front_sys_frolld. On the Main tools menu, click Build and Run Selected Events. This creates and runs the new .adm file. In Review mode, from the treeview, select pickup_swb_front_sys_frolld, and then select Execute Selected Plots. Before creating the plot, you must first determine which request and component contains information on roll angle.

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) Select the curve in the Roll Stiffness vs. Roll Angle plot. Toggle the dashboard visibility to On. Select the Math tab in the dashboard. This shows exactly what Adams/PostProcessor is using to define the X and Y values of the plot. You should see that roll angle (X expression) is defined by the X component of REQUEST_5111. This is what you will use to define the X data in your plot. Create a new page. Change the page layout to 1 view. Select the Data tab. Define the independent axis data with the X component of REQUEST_5111.

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) For the dependent axis, find the roll camber coefficient request. Select the left component and add the curve. Use this plot to answer Question 5 later in this workshop. Exit Adams/PostProcessor. Click Exit, don’t save. Using fingerprint batching Now you will use fingerprint batching to build and run multiple events at the same time.

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) To use fingerprint batching: In Build mode, click Load Model. Click Example Vehicles on the Select File window Double-click car.vdb Double-click systems.tbl and select car_rear_sys.xml and then click Open. The rear suspension of this vehicle is an SLA trailing arm setup. Follow the same procedure to open: d_car_rear_sys.xml from the d_car example vehicles database. This rear suspension is a quadralink strut model. su7_rear_sys.xml from the su7 example vehicles database. This rear suspension is a central link model. In the Test mode bookshelf

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) Expand Suspension Right-click Rear Ride Motion to select Add Event to New Fingerprint Using Model. Select car_rear_sys and click OK Adams/Chassis creates fingerprint_3 and adds the event. Follow the same procedure to add d_car_rear_sys and su7_rear_sys to the fingerprint. For each event in the fingerprint, set up the rear ride motion event with Rise-to-curb at 0, and Jounce Travel and Rebound Travel set to 50 mm. Note: As you change the default settings, the events names are now bold in the treeview. Generally, this means that there have been changes in your session that have not been saved to disk. Tip: Instead of selecting Build and Run Select Events for each model, you can use the Test mode batching feature to do it all.

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) Once all three events are set up, highlight the events in the treeview. Then, select Build and Run Selected Events. Once the events are complete, switch to Review mode. Highlight all three events in the treeview, and then select Overlay Animations check box. Note: Use the default settings. In the property editor, select Animation check box. On the Main tools menu, click Execute Selected Animations Once the animation is complete, return to Adams/Chassis. Select Overlay Plots/Reports of Same Events check box, and then click Execute Selected Plots Using the plots, answer Question 6 later in this workshop.

WORKSHOP 2 – Adams/CHASSIS INTERFACE (CONT.) Section Review What is the front left scrub radius at 50 mm rebound, design, and 50 mm jounce wheel positions?__________________________________________ What is the roll center height at 80 mm rebound, design, and 80 mm jounce wheel positions?________________________________________________ What is the roll stiffness of this suspension at zero roll angle?____________ What is the SDM request ID for front roll camber coefficient?_____________ What is the roll camber coefficient of the pickup_swb front suspension at 0 roll angle?_____________________________________________________ What vehicle model shows the largest camber change over the jounce and rebound travel?_________________________________________________ Which Chassis coordinate system axis points “up”?____________________ Which axis points to the right?_____________________________________ Answer 1: 49.05 mm, 49.02 mm, and 49.09 mm Answer 2: 143.5 mm, 32.9 mm, and –70.1 mm Answer 3: 1.19E6 N*mm/deg Answer 4: 10015 Answer 5: 0.2579 Answer 6: d_car Answer 7: +Z Answer 8: +Y