The effect of a critical micro-void defect on fretting fatigue crack initiation in heterogeneous material using a multiscale approach

Fretting fatigue problems are common in the aerospace and automotive industries, which can seriously affect the fatigue response of the material and the stability of the overall structure. In this paper, the effect of the size, location of single critical micro-void on the fretting fatigue initiation life of heterogeneous materials is studied by numerical simulations and modified critical plane criterion. The theory of critical distance (TCD) is used to consider stress gradients near the crack initiation points. It is shown that when the critical micro-void is located at different positions inside the sample, there is a weakened area similar to the half butterfly wings. This means that when the micro-voids are located in this area, the crack initiation life will be less than that in the case of homogenous material. Furthermore, there are also two enhancement zones. When the micro-voids are located in these two zones, the fretting fatigue life can be increased, that is, at a certain depth below the contact edge and at a certain distance to the right of the contact edge.