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SECTION 2

BASIC CONCEPTS

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● In this section, you learn how to create models in Adams/Car. This module describes the relationships and differences between templates, subsystems,and assemblies, which define Adams/Car models.

Basic Concepts

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● What’s in this section:

● Data Hierarchy

● Test Rig

● Major and Minor Roles

● Naming Convention

Basic Concepts

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Data Hierarchy

● Three levels of files build up a vehicle model (full or half vehicle):

● Template - Defines vehicle sub-assemblies topology (that is, how the parts and joints fit together in the model, how information is transmitted, and so on). For example, a template could be a suspension type, which can be defined either as front and/or rear.

● Subsystem - A mechanical model that references a template and tailors it by supplying parameters that adjust the template (for example, locations that define part dimensions and spring stiffness). These models are usually a major system of your vehicle, for example, front suspension, steering system, and body. The subsystem is a specific instance of the template in which the user has defined new hardpoint positions and property files.

● Assembly - A list of subsystems and a single test rig combined in a vehicle or suspension assembly. A test rig is necessary to provide an actuation, in your model, for analysis.

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Data Hierarchy (Cont.)

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Data Hierarchy (Cont.)

Subsystem File Creation

● The figure shows how a subsystem is created from a template. The template holds default geometry and topology. The subsystem is a specific instance of the template in which the user has defined new model parameters, such as hardpoint positions, property files, and mass properties.

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Data Hierarchy (Cont.)

● You can see the hierarchy of an assembly by selecting Tools Show File (mdi_front_vehicle.asy):

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● A test rig in Adams/Car is the part of the model that imposes motion on the vehicle. Depending on the model and event, different test rigs must be used.

● A test rig is a special subsystem that is connected to all of the other subsystems that make up your model, forming an assembly. The figure on the left shows the suspension test rig alone. With the suspension subsystems, it would look like the figure on the right (an assembly).

Test Rig

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Suspension test rig alone

Suspension test rig assembled with suspension and steering subsystemsSuspension test rig alone

Test Rig (Cont.)

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Major and Minor Roles● Adams/Car uses major and minor roles to create a valid assembly.

Major and minor roles define the location of the subsystem within the assembly.

● Every template (and therefore the subsystem that is created from that template) has a defined major role: suspension, steering, body, anti-roll bar, wheel, and so on.

● When a subsystem is created, the standard user defines the subsystem minor role: front, rear, trailer, or any. This enables the same suspension template to be used for both a front and rear suspension.

● To create a valid suspension assembly, the minimum requirement is a suspension subsystem and the Adams/Car suspension test rig.

● To create a valid vehicle assembly, the minimum requirement is a front suspension, a rear suspension, front and rear wheels, a body, and a steering subsystem.

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Major and Minor Roles (Cont.)

● To add more major or minor roles, use an acarBS.cmd in your working directory with the following commands:

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Naming Convention

For a complete listing, see the Adams/Car online help: Working with Components About the Naming Convention.

● All Adams/Car entities are named after a naming convention. The first three letters of a given entity identify the type and the symmetry rule

● Examples:● gel_arm: General_Part_Left_….● hps_lcs_front: Hard_Point_Single_...● bkl_mount: Bushing_Kinematic_Left_...● nsr_main_spring: Non-linear_Spring_Right_...● pvs_toe_angle: ParameterVariable_Visible_Single_...

S2-14ADM740, Section 2, June 2007Copyright 2007 MSC.Software Corporation