Numerical prediction of fretting fatigue crack trajectory in a railway axle using XFEM

In this paper, we present for the first time the application of a fretting fatigue crack propagation predictive technique to a railway axle subjected to bending fatigue loading condition. We also present the first numerical study on predicting fatigue crack trajectory in an axle and wheel model of a railway axle. The technique is based on combining the eXtended Finite Element Method (XFEM) with two fatigue crack growth criteria, namely Maximum Tangential Stress (MTS) and minimum shear stress range. In the implementation of XFEM, enrichment functions, shifted formulation and overlay elements are adopted. The element crack closure is taken into account using the punctual restriction criterion. To calculate MTS criterion, the stress intensity factors are extracted using interaction integral method, in which mode I and mode II can be separated. The implementation is validated using a complete contact problem and experimental data from literature. It is found the minimum shear stress range criterion provides crack paths closer to the experimental results than those obtained using MTS criterion. The technique is further applied to a Chinese railway axle and the results are compared to the available experimental data. Good agreement between the numerically predicted and experimentally measured crack trajectory in the railway axle is found.