Effect of damping rate on fatigue failure tendency of a topology-optimised swing arm for a heavy commercial truck cab suspension

Abstract

The effect of damping rate on the failure tendency of a truck cab suspension swing arm was numerically investigated. Firstly, the mechanical design of the swing arm was carried out using topology optimisation by taking the standard load cases into account. Displacement differences which occurred in the front cab suspension springs, as a result of the cab roll, were obtained for an uneven road surface by using the Multibody Dynamics (MBD) model of the truck. Using these data, full transient Finite Element (FE) analyses and arm fatigue analysis were conducted for various damping characteristics of the shock absorber. Results showed that, reducing the damping ratio of the shock absorbers by, e.g., 50% in comparison with the reference value, may result in swing arm damage under dynamic loading conditions. Therefore, it was concluded that, damping rate should be considered in the design stage of cab suspension components which can be categorised as a safety system.