Forming process model of rail corrugation based on friction induced torsional vibration determined by vertical dynamics

Abstract

Recently, field measurements show that corrugations are generated on curved tracks and that its wavelength varies with fasteners. The phenomenon that corrugations are generated on curved tracks can be explained with the assumption that corrugation is generated by the torsional vibration of wheelset. This assumption, however, has not been investigated in details yet. In this research, a finite element model including the nonlinear friction-creepage characteristics is developed to analyse the unstable vibration of a wheelset negotiating a curved track, and the results show that the friction induced torsional vibration between inner wheel and rail is most likely to be generated, which can verify the assumption. Furthermore, a mathematical model is developed to illustrate the forming process of rail corrugation, and the results indicate that the corrugation generated on curved track can be attributed to the periodical fluctuation of frictional power due to torsional vibration. Based on the results above, a forming process model of rail corrugation is formulated, which can be applied to explain why wavelength of corrugation varies with fasteners: the vertical dynamics affected by fasteners determine the frequency of torsional vibration and further affect the wavelength of corrugation, indicating the reliability and effectiveness of this forming process model.