AAS 95-455

A Simulation Method for Multibody Dynamics

R. R. Ryan, R. Rampalli and J. F. McGrath, Mechanical Dynamics Inc., Ann Arbor, MI

Abstract

The simulation of mechanical systems can require integration techniques for numerically stiff differential equations, meaning formulations with widely separted time constants. An effective approach to solving the differential and algebraic equations which govern the dynamics of mechanical motion involves partitioning the unknowns in the problem into dependent and independent coordinates and using backward differentiation methods to integrate the independent variables. A linear analysis of an example of interest indicates numerical stiffness. A comparision between the current approach and a non-stiff integration algorithm illustrates the need for the stiff methods.