Three-dimensional analysis of fretting-fatigue problems under variable normal loading conditions: Correlation between experiments and simulations using a non-local approach

This paper deals with the crack initiation life prediction in fretting-fatigue contacts subjected to complex loading conditions, by taking into account the gradient effects arising in such problems. For this purpose, a non-local modelling of the contact region is adopted. This non-local modelling relies on an analogy between contact mechanics and linear elastic fracture mechanics, and enables to take into account the gradient effects independently of the contacting bodies geometry. In this paper, the non-local model is used to predict the crack initiation lives from three-dimensional finite element simulations that are representative of fretting-fatigue experiments carried out under variable normal loading conditions. Since the normal load is time varying, the size of the contact zone changes over time. This variability in time of the contact zone size leads to spatial dispersion of the damage on the contact surface, which is accounted for in the crack initiation life prediction. In order to show the prediction capability of the non-local model, the predicted crack initiation lives are confronted to the experimental crack initiation lives. Lastly, the non-local model is directly applied to mechanical fields captured during fretting-fatigue experiments. To do so, the Digital Image Correlation (DIC) technique is used to measure the experimental mechanical fields during the experiments.