CRACK INITIATION CRITERIA IN FRETTING FATIGUE

This paper is a description of a series of fretting fatigue tests on an Al/Cu alloy in which the contact size was varied while the other relevant parameters were held constant. The fretting fatigue life was found to be infinite below a certain critical contact width. The configuration has been analysed using elastic stress analysis and stresses and displacements have been calculated. The variation of life with contact size can be explained by a variation in amplitude of micro-slip. Composite parameters proposed by Ruiz et al. are shown to characterize the severity of fretting damage and the probability of crack initiation, and hence explain the observed results. The physical basis of these parameters and their use in design calculations is discussed. © 1990.