Altair Road Modeling

This section outlines the road models that have been implemented as part of Altair’s road library. You can choose to use this implementation when using a Durability tire with cam contact by selecting the road file in the Auto Tire auto entity dialog using the “Road Property File” browser as shown below.

Figure 1.

The following types of road models are supported:

2D Roads

2D or two-dimensional roads start as an infinite, flat surface in the X-Y directions, with the Z axis being normal to the plane. The X, Y, and Z directions and the origin of the road are given by the road reference marker. Onto this plane you can add obstacles like potholes and planks to excite the vehicle through the tire.

All 2D roads share three common parameters:
Parameter Description
OFFSET Distance by which road x coordinate has to be moved with regard to road reference marker.
MU Coefficient of friction.
ROTATION_ANGLE_XY_PLANE Angle by which the road has to be rotated about road reference marker’s Z axis at the origin of the road in anti clock wise direction.

When not mentioned by the user OFFSET and ROTATION_ANGLE_XY_PLANE will be considered as 0. MU will be considered as 1.0.

CRG Road

Specify an accurate representation of road undulations that cannot be captured using primitive geometric shapes.

Point Cloud Data

The road is represented by a set of triangular mesh elements. Here the road data file contains a set of points on the road surface and a set of connectivity data to associates three points with a triangular element.

Spline Road

Specify a road in three dimensions, with center line data, which is interpolated using a Spline.
  1. Spline Road with 2D Obstacles: Specify a Spline road by overlaying 2D obstacles (shapes which produce two dimensional effects on road undulations).
  2. Spline Road with 3D Obstacles: Specify a Spline road by overlaying 3D obstacles (shapes which produce three dimensional effects on road undulations).

The ROTATION_ANGLE_XY_PLANE term in the [PARAMETER] block wherever mentioned can be used to rotate the road on top of the road reference marker.