• An elastoplastic peridynamic model was established to simulate flexible wheel-rail thermal contact. • Validation was conducted by comparing the results of the peridynamic model and finite element model. • Thermal softening is the primary cause of surging plastic deformation and wear. • This study reveals the friction heat-dominated mechanism of wheel-rail surface scratches. The thermomechanical loads generated by sliding contact markedly exacerbate plastic deformation and even induce damage at the wheel-rail interface, thereby accelerating the failure of the wheel-rail system. This study establishes a flexible wheel-rail model using ordinary state-based peridynamic (PD) thermomechanics to explore the thermomechanical response and damage mechanisms of the wheel-rail interface under sliding contact. Model validation was conducted by comparing thermomechanical results from the PD model with those from the finite element model. A parametric study using the established PD model was conducted to investigate the effects of creepage, friction coefficient, and vehicle speed on the plastic deformation and damage behavior of the wheel-rail interface. The increase in frictional heat flux, driven by higher levels of creepage, friction coefficient, and train speed, results in a sharp elevation of the contact temperature (approximately 450 to 1450°C). Interfacial heat conduction results in comparable temperatures between the wheel and rail surfaces. The strength reduction induced by thermal softening led to excessive plastic deformation at the wheel-rail interface, and ultimately to material wear. In critical sliding contact conditions, the temperature exceeds 800°C, followed by a rapid cooling rate exceeding 1000°C/ms, leading to thermal-induced martensitic white etching layers formation. The microstructural characteristics of the field rail samples provide qualitative support for the thermomechanical damage features predicted by the PD model.
Wang et al. (Sat,) studied this question.