Using the fatigue crack initiation parameter for prediction of the crack location on a curved track by 3D-FE analysis

Abstract

Dynamic modeling of wheel-rail interaction is significant in accurate fatigue analysis of railways. Both location and magnitude of the contact stresses in the contact area must be evaluated accurately and efficiently via computational tools. In curved railway tracks, the distribution of the force exerted on the wheel is complex as it is multiaxial rather than uniaxial; thus, a more comprehensive computational model is required. In this work, a numerical procedure is developed to investigate the fatigue crack initiation on the curved tracks. The Universal Mechanism software is used to specify the spectrum of axial wheel force as input to a three-dimensional explicit finite element model to obtain the resulting stresses at the wheel-rail contact region. A critical element with the maximum von Mises stress value is treated as the element where the fatigue crack is most probably to be initiated. In this element, the critical plane method is used to determine the orientation of the crack initiation. The effect of the radius and slip ratio on the exact site of fatigue crack initiation is established in this approach, and the contact point influence on the fatigue crack initiation parameter is investigated. The proposed model successfully predicts a practical wheel-rail dynamic response to cyclic loading, applying the geometry of the curved track.