Investigation on dynamic responses of vehicle due to wheel polygonalization
The polygonal wear around the wheel circumference could pose highly adverse influences on the wheel/rail interactions and thereby the performance of the vehicle system. In this study, the effects of wheel polygonalization on the dynamic responses of a high-speed rail vehicle are investigated through development and simulations of a comprehensive coupled vehicle/track dynamic model. The coupled model of the high-speed vehicle integrates flexible slab-track, wheelsets and axle boxes models so as to account for elastic deformation responses caused by impact loads induced by the wheel polygonaization. A field-test program was undertaken to acquire the polygonal wear profile and the selected dynamic responses of a high-speed train, and the data are used to demonstrate validity of the coupled vehicle/track model. Subsequently, the effects of wheel polygonalization are evaluated in terms of wheel-rail impact forces, axle-box vertical acceleration and dynamic stress developed in the axle considering different amplitudes and harmonic orders of the polygonal wear. The results suggest that the high-order wheel polygonalization can give rise to high frequency impact loads at the wheel/rail interface, and excite some of the vibration modes of the wheelset and the axle box leading to high magnitude axle box acceleration and the dynamic stress in the wheelset axle.