Contact-evolution based prediction of fretting fatigue life: Effect of slip amplitude

Fretting fatigue is a complex problem and therefore it has generally been necessary to determine fatigue lives experimentally. This paper describes a method that integrates wear modelling with fretting fatigue analysis to permit the prediction of the effects of material removal, due to fretting wear, on fretting fatigue life. A finite element based method is employed to predict the fretting wear-induced evolution of contact geometry, contact stresses and a multiaxial fatigue damage parameter with cumulative damage effects, as a function of slip amplitude, for a laboratory fretting fatigue test arrangement. The results show that the approach is capable of capturing the experimentally observed effect of slip amplitude on fatigue life. The conditions simulated span across a range of partial slip and gross sliding conditions, corresponding to fretting fatigue tests available from the literature, and giving rise to the well-known phenomenon of a critical range of slip amplitude for reduced fatigue life. The methodology demonstrates that this is primarily due to wear-induced pressure redistribution, the nature of which is highly dependent on the slip regime.