Vehicle and Guideway Modelling: Suspensions Systems

Performance, safety and comfort of a vehicle are related to its low frequency motions. The corresponding mechanical models are characterized for all kinds of vehicles by stiff parts represented as rigid bodies and soft components like springs, dampers and actuators. The method of multibody systems is most appropriate for the analysis of vehicle motions and vibrations up to 50 Hz. In this contribution the derivation of the equations of motions of multibody systems is shown step by step up to the computer-aided evaluation of these equations.

Starting with kinematics for rigid body vehicle systems, the foundations of dynamics together with the principles of d’Alembert and Jourdain are used to get the equations of motion. Then, some aspects of multibody dynamics formalisms and computer codes for vehicle dynamics are discussed. Further, models of randomly uneven guideways are presented. Performance criteria for ride comfort and safety are considered. Finally, the analysis of the suspension of a car model is presented in detail.