Flat-Induced Wheel-Rail Impact Response under Thermo-Mechanical Loading

摘要

The vertical wheel-rail impact response induced by a wheel flat under thermo-mechanical loading was investigated numerically based on a 3-D wheel-rail rolling contact model. Thermal stress distributions of the wheel and rail generated by the frictional heating during the wheel-rail slip were firstly simulated, and then the corresponding results were inputted into the finite element model of LS-DYNA/explicit code as an initial pre-stress, to investigate the wheel-rail impact response. Influences of five train speeds, three flat lengths and five axle loads were discussed. The results show that the maximum thermal stresses are occurred on the tread of the wheel and the top face of the rail, respectively. The thermal loading has been demonstrated to contribute to weaken the maximum vertical impact force, maximum von-Mises equivalent stress, and the resistance to plastic deformation. Besides, the wheel-rail impact responses induced by a wheel flat under thermo- mechanical loading are sensitive to the train speed, flat length, and axle load.