WORKSHOP 8 TIRE TESTRIG TUTORIAL

Tire Testrig Problem Statement: In this workshop, you will learn how to use the new Tire Testrig available in Adams/Car. The testrig provides the ability to visualize the effects of tire properties and compare tire model performance. The testrig provides the capability to easily produce plots of tire characteristics using a tire property file and a list of inputs.

Tire Testrig The tire testrig model consists of single tire (wheel) mounted on a spindle that can be suspended to ground by a spring, or preloaded by a single component force or fixed at a certain axle height. The road can be fixed or moving (moving in x, y, z-direction, or rotating around x-axis), while the road itself can be flat with or without a cleat (pothole), or user-defined (road property file). The wheel movements can enhance steering (slip angle variations), wheel rotations (longitudinal slip variations), inclination with the road (camber), vertical and longitudinal wheel (center) displacements.

Tire Testrig The procedures to use Tire Testrig: This workshop is split into two parts. One where the default loadcase file is being used and one where you create your own loadcase file. Using the shared tire loadcase file Run a loadcase file with the tire testrig Reviewing the results in Adams/Postprocessor Creating a tire loadcase file

Tire Testrig Using the shared tire loadcase file: In this section you will see how to use and modify the existing tire loadcase file. The default loadcase file (combined_slip_test.xml) has been provided in the loadcase.tbl under acar_shared_database. This loadcase has four analyses which define four experiments for the tire testrig. The tire characteristics at different slip angles are measured. A longitudinal slip sweep is carried out at each of the slip angles of interest (0, 2, 5, and 10 degrees).

Tire Testrig Run a loadcase file with the tire testrig: Open Adams/Car session. Click Simulate -> Component Analysis -> Tire Testing The Tire Testrig screen will appear

Tire Testrig Run a Loadcase file with the tire testrig (Cont.): Click File->Open and select the combined_slip_test.xml from the shared database The Tire Testrig screen shows the four analyses defined in the combined_slip_test.xml for the tire. Click Run It. After submitting the job a dialog box pops up indicating the Tire Testrig plots are available.

Tire Testrig Reviewing the results in Adams/Postprocessor: The Adams/Postprocessor is automatically displayed in plotting mode once the analysis is complete. In the tree view on the left highlight each page to display the plots of various tire curves.

Tire Testrig Creating a tire loadcase file: You will create a new tire loadcase file. Here, you will compare two Fiala tire property files with different CSLIP parameter. Note: The mdi_fiala02.tir required in this workshop is provided in your acar_training_MD.cdb database. Open Adams/Car session Click Simulate -> Component Analysis -> Tire Tesring Click File -> New. Enter name in the New File window as new_loadcase_fiala. Click OK

Tire Testrig Creating a tire loadcase file (Cont.): You will be prompted with following window.

Tire Testrig Creating a tire loadcase file (Cont.): Select “mdi_fiala01.tir” provided in acar_shared_database. Click Kinematics tab. In the Tire Radius field use the radius in the tire property file. Change Wheel Spin Motion to have Long_slip_sweep and the Amplitude to be 100 as shown in the figure below. Click the Out of Plane tab and set the slip and inclination angle values to be 0

Tire Testrig Creating a tire loadcase file (Cont.): Click on Enter name for the new analysis in Name field . Click Add to add a second analysis analysis_2. This is where the user can modify solver parameters like End Time, Number of Steps, Error Tolerance, Integrator etc.

Tire Testrig Creating a tire loadcase file (Cont.): Double click on analysis_2 -> Select Tire tab -> Select tire property file as“mdi_fiala02.tir” from the database acar_training_MD.cdb. This tire property has modified CSLIP parameter. Make sure the other inputs to the testrig match those for analysis_1. Click Save As to save this loadcase file in your acar_training.cdb directory. Click Run It. After submitting the job you get information window when the plots are ready. Click OK

Tire Testrig Reviewing the results in Adams/Postprocessor: Adams/Postprocessor is launched when the plots are ready. Look at the Longitudinal Force vs. Slip plot. The red curve show the response when CSLIP=1000 and the blue one when CSLIP=1800.

Tire Testrig Relevant Simcompanion Articles: Additional and optional information on the brief overview of the parameters used as inputs by the testrig can be found in the Simcompanion article. ATR-002: Using the Tire Testrig Simcompanion article #: KB8017771 http://simcompanion.mscsoftware.com/infocenter/index?page=content&id=KB8017771