Wheel-rail elasto-plastic cyclic rolling-sliding-impact behaviour under thermo-mechanical loading

Friction heat will aggravate plastic deformation and performance degradation in wheel-rail system. In this study, a three-dimensional (3D) thermo-mechanical coupled finite element (FE) model of wheel-rail cyclic rolling contact was developed, incorporating strain hardening, strain-rate strengthening and thermal softening effects. The evolution of temperature, stress and strain during wheel-rail rolling-sliding contact was examined, and influences of creepage, train speed and rail corrugation-induced impact were evaluated. The results indicate that contact temperature and residual stress/strain accumulate progressively after four wheel passages. For a corrugated rail under train speed of 400 km/h and 20% creepage, the surface temperature can reach 748.8°C, which may trigger phase transformation of rail material. Thermal effect will significantly enhance the residual stress/strain amplitudes and accelerate wheel/rail damage under higher creepage, and creepage exerts a more pronounced effect on wheel-rail thermo-mechanical response than train speed. These findings will support wheel-rail design and safety assessment in extreme conditions.