6.2 Types of Analyses

There are two types of analyses that you can run in ADAMS/Car: suspension analyses and full-vehicle analyses. To run full-vehicle analyses, you must have purchased the ADAMS/Car Vehicle Dynamics package.

1. About Suspension Analyses

ADAMS/Car lets you analyze and view virtual prototypes of suspensions and steering subsystems. Using ADAMS/Car, you can:

• Easily modify the topology and the properties of the components of your suspension.

• Run a standard set of suspension and steering maneuvers.

• Visualize suspension characteristics through plots.

For a suspension analysis, you can specify inputs to:

• Move the wheels through bump-rebound travel and measure the toe, camber, wheel rate, roll rate, side-view swing-arm length, and other characteristics.

• Apply lateral load and aligning torque at the tire contact path and measure the toe change and lateral deflection of the wheel.

• Rotate the steering wheel from lock to lock and measure the steer angles of the wheels and the amount of Ackerman, which is the difference between the left and right wheel steer angles.

Based on ADAMS/Car results, you can alter the suspension geometry or spring rates and analyze the suspension again to evaluate the effects of the alterations.

2. About Full-Vehicle Analyses

ADAMS/Car lets you analyze virtual prototypes of full vehicles. Using ADAMS/Car, you can:

• Easily modify the geometry and the properties of the components of your subsystems.

• Select from a standard set of vehicle maneuvers to evaluate handling characteristics of your virtual prototype.

• View the vehicle states and other characteristics through plots.

6.3 Introducing Suspension Analyses

You can test suspensions to determine their kinematic and compliance characteristics by performing wheel travel, static load, and steering analyses. This chapter explains how to run suspension analyses and describes each type of suspension analysis you can run.

6.3.1 Suspension Analysis Process

You perform a suspension analysis to learn how a suspension controls the wheel motions and transmits load from the wheels to the chassis. To perform a suspension analysis, you first create or open a suspension assembly that contains the selected subsystems and the test rig. You then specify ranges of vertical wheel travel, steering travel, and static tire contact patch loads and the number of solution steps.

During the analysis, the test rig articulates the suspension assembly in the specified number of steps and applies the inputs you specified. At each step, ADAMS/Car calculates over 38 suspension characteristics, such as toe angle, camber angle, track change, wheel base change, wheel rate (vertical stiffness), fore-aft wheel center stiffness, and so on. You can plot these characteristics and use them to determine how well the suspension controls the motions of the wheels.

Figure 6.1 shows an overview of the process.

Figure 6.1 Suspension Analysis Process

A suspension analysis in ADAMS/Car is a quasi-static equilibrium analysis.

6.3.2 Suspension Assembly Roles

To create a suspension assembly, you can select any subsystem that has either a suspension or a steering major role. A major role defines the primary function of the subsystem.