Effects of Nonlinear Suspension Stiffness on Vehicle Chassis Dynamics

Abstract Suspension systems play a critical role in vehicle dynamics, handling, and ride comfort; however, their stiffness characteristics are often nonlinear, making it challenging to predict their influence on overall vehicle behavior. Although previous studies have employed lumped-parameter models to investigate nonlinear vehicle dynamics, such simplified approaches are limited in their ability to capture the local responses of deformable chassis structures. To address these limitations, this study introduces a computational framework that integrates finite element modeling with a reduced-order technique, namely, the Craig–Bampton component mode synthesis (CB-CMS) method, to investigate the influence of suspension stiffness configurations on the dynamic responses of a flexible vehicle chassis. Particular attention is given to local displacements and structural deformations under pitch, roll, and combined pitch and roll excitations. The proposed framework enables efficient and accurate computation of chassis dynamics. The results show that the strongly nonlinear suspension stiffness configuration exhibits lower peak displacement and deformation amplitudes of the chassis structure than the linear configuration within the investigated excitation frequency range. These findings highlight the importance of suspension stiffness characteristics in chassis modeling and suspension system design, and the proposed framework provides an efficient and versatile tool for analyzing the nonlinear dynamics of deformable vehicle structures.