A study of formation of high order wheel polygonalization

Abstract High frequency and high magnitude wheel-rail impact forces caused by high order wheel polygonalization have been associated with service failures of different structural components in high-speed rail vehicles. In this study, a long-term wear iterative scheme was developed to identify primary contributors of high order wheel polygonalization and its propagation over the service period. The wear model was formulated by integrating an Archard wear model to a coupled vehicle/track dynamic model of a high-speed railway car. The effects of different vehicle and track parameters such as the flexibilities of wheelset and rail, vehicle speed, wheelbase, and rail pad stiffness and damping on the wheel wear were further investigated. The bending vibration mode of the rail segment between two wheelsets, regarded as three half wavelength bending vibration mode near 650 Hz, was identified as the primary contributor to high magnitude wheel/rail contact force in the 500–800 Hz frequency range. This represented a nearly fixed-frequency loading condition. Variations in the vehicle speed and the track could help distribute wheel circumferential irregularities over a broader range of wavelength and thereby mitigate the growth rate of wheel polygonalization of a single order. It is further shown that the wheelset flexibility and higher rail pad stiffness accelerate the wheel wear and more likely contribute to the lower order wheel polygonalization. Increasing the rail pad damping could effectively reduce the rate of growth of high order wheel polygonalization.