Effect of manufacturing residual stress on the fatigue life of railway wheels for heavy-haul transportation

Abstract

The present work aims to compare the effect of the residual stress from the thermal treatment process (TTP) on the estimate of fatigue life of railway wheels - class C, both with and without residual stresses field from thermal treatment process. A 3D finite element method model is used to calculate the thermal treatment process and the rolling contact between rail and wheel. With the stresses calculated in this region, the study estimates the life under fatigue until a crack arises. The crack, when propagated, can result in shelling, which is one of the types of failure with significant economic importance to railroad maintenance. The model primarily uses the elastoplastic approach, then adds residual stresses from the thermal treatment process of railway wheels. ABAQUS® software is used for the numerical processing, in parallel with specially developed techniques to reduce the computational cost without causing loss of accuracy of the results. The fatigue life of the railway wheel before crack initiation is determined by the modified Dang Van high-cycle fatigue criterion. Given the assumption that the wheel radius does not change during rolling, the elastic shakedown phenomenon occurs in a few loading cycles. The high-cycle life for the wheel is estimated using the variation in the stress field, both with and without residual stresses from the thermal treatment process. The results of the numerical simulation showed that the von Mises stresses in railway wheels with thermal residual stresses are lower than in wheels without thermal residual stresses. The elastic shakedown phenomenon happened in three load cycles in the wheel model with thermal residual stress and in four load cycles for in the wheel model without thermal residual stress. However, this small difference in cycles caused by the thermal treatment process has a significant effect on the fatigue life. The modified Dang Van’s fatigue criterion showed that railway wheels with thermal treatment have 43.2% more life than railway wheels without it.