Abstract
Keywords - Multi-body dynamics, FEA, MacPherson suspension, S-shape spring, Side force
Abstract - With the increase of vehicle speed, the ride and handling performances of any vehicle become more important, which demands strict requirements on suspension design.
Because of the limits of MacPherson strut suspension structure design, the lateral dead load and dynamic load inevitably exist on suspension damper, which are liable to result in damper piston rods side wear to shorten the life span of dampers. Furthermore, the side load increases the inner friction between damper components, which decreases the performance of suspension system. Aiming at above problems, this paper proposes to adopt an S-shape spring with inconstant curvature diameter to improve and optimise MacPherson strut suspension design, in order to significantly reduce side load on suspension damper for piston rod protection.
Taking a small car as example, this paper uses 3D solid CAD modelling software-Unigraphics to build up a detailed front suspension model. In the environment of multi-body dynamics analysis software, ADAMS, a detailed multi-body rigid-elastic coupling dynamics model is built to simulate the value of side force and the angle of suspension force. The theoretical curvature of centreline is deduced and rectified by Finite Element analysis. An FEA spring model is built according to the simulation result in ADAMS and the finite element analysis is performed. So the optimal design for the suspension components, particularly for the spring design is obtained.
The study shows that if the S-shape spring is properly designed, it would decrease the side load of MacPherson strut suspension damper significantly so the product service life can be extend. Also the ride and handling performance can be improved.