Abstract: During the process of high-speed trains service, different degrees of low-frequency hunting motion always occur and large-amplitude of hunting motion can significantly deteriorate the wheel-rail rolling-contact relationship and threaten vehicle-operation safety. Based on the vehicle-track coupled dynamic theory, the high-speed train-track spatial coupled dynamic model was established in this paper, in which the non-Hertzian wheel/rail rolling-contact model was considered. With an adaptation of the numerical model, the wheel-rail interaction mechanism of high-speed trains under hunting conditions with different wear wheel/rail profile matching states was systematically compared. The results show that under the hunting conditions the dynamic stress distribution of high-speed trains vibrates periodically and wheel-rail contact-stress distribution under the hunting condition is significantly higher than that under the steady-state operation condition. The adhesion characteristics of the wheel and rail under hunting conditions are much worse than those under steady-state operation condition, and the adhesive region will decrease as wheelset lateral displacement rate is increase. At the same time, the wear-depth distribution under the hunting conditions is much higher than that under the steady-state operating conditions.

Key words: high-speed train, hunting motion, vehicle-track coupled dynamics, wheel-rail non-Hertzian contact, wear