An elastic-plastic theoretical analysis model of wheel-rail rolling contact behaviour

An accurate wheel-rail contact theoretical model is crucial for predicting wheel-rail wear and rolling contact fatigue. The plastic damage occurs frequently in the high-speed wheel-rail contact area at present; however, the state-of-the-art wheel-rail rolling contact theoretical models hardly take into account plastic behaviour. In this study, a three-dimensional elastic-plastic theoretical analysis model of wheel-rail rolling contact was established, based on the Vermeulen-Johnson (V-J) rolling contact theory and the bilinear hardening model. The stress distribution of the elastic-plastic wheel-rail contact area was expounded, the analytical formula of elastic-plastic creep force/creepage was derived, and the mapping relationship of wheel-rail elastic-plastic creep force/creepage was constructed. Besides, the strain rate effect of wheel/rail materials on the elastic-plastic creep force/creepage curve was also investigated. Finally, the proposed elastic-plastic theoretical model was verified by the corresponding experimental and finite element simulation results. The results indicate that the plastic deformation in the wheel-rail contact area leads to a decrease in the initial slope of the creep force/creepage curve, but an increase in the saturation creepage. The strain rate effect increases the initial slope of the elastic-plastic creep force/creepage curve. The proposed theoretical model is of great significance to the damage assessment of high-speed wheel-rail systems.