A contribution to shock absorber modeling and analysis of its influence on vehicle riding features

Shock absorbers are fundamental part of the vehicle suspension. Suspensions are needed to guarantee vehicle handling and passenger riding comfort. For good handling and braking performance of the vehicle, the tire-road contact forces need to be as stable as possible. Each wheel should always remain in contact with the ground. Comfort means that vibrations, induced by road profile during riding, are of a minimal nuisance to the passengers. When designing a new vehicle, a lot of development effort is focused on the optimal choice of the suspension parameters, stiffness and damping. This paper presents some results of an experimental study conducted on three shock absorbers that are in current production at Magneti-Marelli. Experimental tests were performed in conditions of random excitation. Based on the characteristic diagrams that correlate Forces with the kinematic values (Displacement, Velocity, Acceleration), by means of the "black box" method a mathematical model of the shock absorber response has been identified. The influence of the shock absorber on vehicle riding features are analysed by observing the vehicle responses to poly-harmonic excitation function