Analyses of contact pressure and stress amplitude effects on fretting fatigue life

Elastic-plastic finite element analyses of a cylinder-on-plate configuration, studied experimentally, were performed to provide an explanation for the decrease in fretting fatigue life with increasing contact pressure. Three values of normal load, namely 1338 N, 2230 N, and 3567 N, and three stress ratios (0.1, 0.5, and 0.7) were considered. Based on a previously determined dependency between contact pressure and friction coefficient, the effect of coefficient of friction was also evaluated. The deformation remained elastic under all conditions examined. Cyclic, interfacial stresses, and slips were analyzed in detail. The amplification of remotely applied cyclic stress in the contact region is shown to provide a rationale for the effect of contact pressure and stress amplitude on life. Comparisons with previous experiments indicate that the local stress range computed from finite element analysis may be sufficient for predicting fretting fatigue life. Further, the results suggest that the slip amplitude and shear traction may be neglected for this purpose.