Research into the problem of wear creating a polygon-shaped wheel on metro trains

Abstract

The reasons for wear of a wheel to create a polygon-shaped wheel on metro trains are analysed in this paper. Analysis of wear data leads to the conclusion that it is mainly structural vibration of the wheelset that causes the wear that creates polygon-shaped wheels. After analysing the characteristics of the structure and vibration of the vehicle, a model that considers wheelset flexibility is established. We then analyse the effects of flexible deformation of the wheelset on vertical force, creepage and creep force in wheel/rail rolling contact, and find that the main wheel wear frequency is 35.98 Hz. As for the question of how many faces the worn polygon-shaped wheel displays, we propose that the nature of the wear to create the polygon-shaped wheel depends on the average running speed of the vehicle. This relationship accounts for the apparent contradiction of a fixed vibration frequency and variable vehicle speed leading to wear to create a polygon-shaped wheel, and shows how a multi-faced polygon can be caused by a low-frequency vibration between wheel and rail.