Numerical stress analysis of rail rolling contact fatigue cracks

The paper presents the results of the stress analysis of rail rolling contact fatigue cracks. The basis of the model used in the analysis is the finite element approach which enables the crack tip stress environment to be described by the fracture mechanics crack tip stress intensity factors (SIFs) K-I, K-II, and K-III. The results for a semi-elliptical crack perpendicular to the rail axis and the ''squat'' type of crack are presented. An influence of such factors as crack inclination angle, residual stresses, a traction load acting on the rail surface and the pressure of liquid trapped in the crack is presented as the results of 2D modelling. Distributions of contact normal and tangential forces at the rail surface and inside the crack are determined. Variations of the SIFs K-I, K-II, and K-III for the 3D, and K-I, K-II for the 2D cases during rolling of a wheel over the crack are plotted against the wheel positions. Distributions of the SIFs along the ''squat'' type crack front for various locations of the wheel are also presented.