Study of the simulation model of a displacement-sensitive shock absorber of a vehicle by considering the fluid force

Abstract In this study, a new mathematical dynamic model of a displacement-sensitive shock absorber (DSSA) is proposed to predict the dynamic characteristics of an automotive shock absorber. The performance of a shock absorber is directly related to the vehicle behaviour and performance, for both handling and ride comfort. The proposed model of the DSSA is considered as two modes of the damping force (i.e. soft and hard) according to the position of the piston. In addition, the DSSA is analysed by considering the transient zone for more exact dynamic characteristics. For the mathematical modelling of the DSSA, flow continuity equations at the compression and rebound chamber are formulated. The flow equations at the compression stroke and rebound stroke respectively are formulated. Also, flow analysis of the reservoir chamber is carried out. Accordingly, the damping force of the shock absorber is determined by the forces acting on both sides of the piston. The characteristics of the damping force are observed by the proposed method. The analytical results of the damping force characteristics are compared with the experimental results to prove the effectiveness. In particular, the effects of the displacement-sensitive orifice area on the damping force and the effects of the displacement-sensitive orifice length on the damping force are observed. The results reported herein will provide a better understanding of the shock absorber.