Dynamic and Fatigue Study of the Automotive Upper Arm Suspension System

Optimum design of an automotive part under random loading must satisfy two principal conditions: a safe fatigue life and a natural frequency far from the road power spectral density spectrum. Dynamic behaviour of the upper arm suspension was modelled solving the equation of motion. The quasi-static analysis was used in this study as it is highly efficient when the frequency of excitation is below the resonance frequency. The fatigue life was calculated from the multiaxial criterion equivalent to the uniaxial one based on Strain Energy Density. Finally, the critical elements were detected using a Matlab interface developed in previews work.