Analysis of an unusual McPherson suspension failure

In this paper the cause of premature failure of the upper strut mount of a McPherson suspension is investigated. The work was prompted by the fact that the failed component has been used for at least four decades by a car manufacturer without reporting any premature failure and therefore an in depth study of the structural behavior of the component was required. Both experimental tests and numerical analyses have been carried out in order to estimate the service life of the component. The fatigue life of the component has been assessed by a defect tolerant analysis. The result of the investigation is that the upper strut mount failure was due to an impulsive load that can not be justified by the static and dynamic loads acting on the component caused by road irregularities and vehicle manoeuvring during usual working conditions.