SYMBOLIC QUASI-STATIC AND DYNAMIC ANALYSES OF COMPLEX AUTOMOBILE MODELS

SUMMARY This paper describes how quasi-static and dynamics analysis methods are combined to simulate of a “full-scale” passenger car model. It also describes a novel method for combining symbolic and numerical equation formulations to generate quasi-static analysis algorithms. A quasi-static model is first used to simulate three-dimensional suspension kinematics and compliance properties. The results from this analysis are then used to fit coefficients to polynomials that describe the suspension motions. These coefficients are then employed in a dynamics model that is formulated using the same polynomial equations. The method is illustrated for an automotive vehicle model, using a suspension representation with 11 degrees of freedom (DOF), and a full-vehicle model with 14 DOF. The symbolic multibody program AUTOSIM is used to derive the equations and optimize them for computer solution. The overall simulation is sufficiently detailed to captures the influences of bushing compliances, and yet is computatio...