Fatigue analysis of railway wheel using a multiaxial strain-based critical-plane index

A fatigue damage model to assess the development of subsurface fatigue cracks in railway wheels is presented in this paper. A 3-dimensional finite element model (FEM) is constructed to simulate repeated cycles of contact loading between a railway wheel and a rail. The computational approach includes a hard-contact over-closure relationship and an elastoplastic material model with isotropic and kinematic hardening. Results from the simulation are used in a multiaxial critical-plane fatigue damage analysis. The employed strain-based critical-plane fatigue damage approach is based on Fatemi-Socie fatigue index that takes into account the non-proportional and out-of-phase nature of the multiaxial state of stress occurs when a railway wheel rolls on a rail. It predicts fatigue-induced micro-crack nucleation at a depth of about 3.7mm beneath the wheel tread, as well as the crack plane growth orientation which indicates the possible failure pattern. Additionally, the influence of various factors such as contribution of normal stresses, higher wheel load, and material model have been investigated.