INFLUENCE OF CONTACT LOADING ON FRETTING FATIGUE BEHAVIOR

Fretting induced cracking is commonly observed in industrial components that are in contact and are subjected to small oscillatory movements between them. Fretting causes a considerable reduction in fatigue strength. In this paper recent knowledge on the short and long crack growth behaviour is applied to estimate crack propagation and fatigue life in fretting. The model is based on mode I stress intensity factors with a threshold modified for short cracks. The predicted results are compared with experiments and the influence of the contact pressure is examined. A good correlation between predictions and experimental results are obtained for crack growth rates as well as fatigue lives in terms of number of cycles to failure. It is seen that the increase of fatigue life observed for contact pressures above a certain level can be predicted by the crack growth model.