Influence of wheelset wear and wheel radius difference on dynamics performances of high-speed train

Wheel profiles of working high-speed train were traced in test to study the change rules of shape and position of rolling radius difference function with worn profiles and wheel radius difference. The dynamics model of high-speed train was set up based on the parameters of working high-speed train to calculate nonlinear critical speeds, stabilities, and curve passing performances under different conditions of worn profiles and wheel radius difference. The relationship between rolling radius difference function and vehicle dynamics performances was described by the calculation of dynamic equilibrium points at different wheel-rail contacts under straight and curve passing conditions of high-speed train. Analysis result indicates that profile wear and radius difference may change the shape and position of rolling radius difference function, cause the change of equilibrium points of wheel-rail contact and lead to the significant change of vehicle system dynamics performances at the end. On straight line, when the running distance of vehicle reaches 1.98×10⁵ km, vehicle critical speed declines from 530 km·h^-1 to 300 km·h^-1 with the increase of profile wear. Vehicle riding index increases from 1.60 to 1.87. As wheel radius difference changes from-0.5 mm to 0.5 mm, the critical speed declines by 80 km·h^-1, while the riding index increases by 0.10. On curve line, with the increase of profile wear, wheelrail lateral force increases from 6.7 kN to 15.9 kN. Derailment coefficient increases from 0.12 to 0.23. Elkins wear index increases from 0.005 to 0.018. As the wheel radius difference changes from-0.5 mm to 0.5 mm, wheel-rail lateral force decreases by 3-6 kN, derailment coefficient decreases by 0.03-0.10, and Elkins wear index decreases by 0.003-0.010.