Study on the effect of residual stresses on fatigue crack initiation in rails

Abstract

Rolling contact fatigue cracks shorten rail service life, and increase costs of rail maintenance and replacement significantly. The aim of the present study is to investigate the effect of residual stresses induced by manufacturing and repeated wheel-rail contact on fatigue crack initiation in rails. To this end, three-dimensional finite element models of rail on-line heat treatment, rail straightening, and wheel-rail contact were established to study the state of residual stresses of on-line heat-treated rails. The effect of residual stresses induced by rail manufacturing and repeated wheel-rail contact on fatigue crack initiation was analyzed based on a fatigue parameter FPmax by Jiang–Sehitoglu low cycle fatigue criterion. Rail fatigue crack initiation mechanism under the combined action of wheel load and residual stresses was studied. The results show that residual stresses induced by rail manufacturing affect the stress state of on-line heat-treated rails after repeated wheel loads. The influence of residual stresses induced by rail manufacturing and repeated wheel-rail contact on the FPmax of rails is significant. However, there is no positive or negative correlation between residual stresses and FPmax of rails under different wheel loads and friction coefficients.