An analysis of the relationship between suspension geometry and ride characteristics

Wheel rate is an important parameter for ride analysis. It might alter, due to a change in suspension geometry. A closure equation is used to calculate the geometric ratio between spring axial deformation and vertical wheel travel, i.e., the installation ratio. Force analysis is used, to obtain the force ratio between the force acting on the spring and the vertical load on the wheel. Then, a new approach to calculate the wheel rate, according to its essential definition-the vertical force per unit vertical displacement, at the location along the spindle corresponding to the wheel centerline-is proposed and applied for Double-Wishbone and MacPherson strut suspension. A ride analysis of the non-linear model, for varied wheel rate, is undertaken in the frequency domain. ADAMS/Ride is used to verify the proposed approach with random road signal in the time domain. Preliminary simulation results show that specific suspension geometries fundamentally affect ride characteristics.