The Formation Mechanism of High-Order Polygonal Wear of Metro Train Wheels

Wheel polygonisation is a wavy wear on wheel’s circumference, which aggravates the wheel-rail interaction and prematurely invalidates or damages the components of vehicle-track system. This paper presents an investigation into the formation mechanism of high-order polygonal wear of metro train wheels through field experiments and numerical simulations. Some necessary field experiments are conducted to obtain the characteristics of the irregular wear of the wheels and the dynamics responses of the vehicle components. The numerical modal analysis of vehicle’s key components is performed. Furthermore, a long-term wheel wear model is built including a vehicle-track dynamics model coupled with a local wear model. The metro vehicle-track coupled dynamics model considers the flexibilities of the wheelset and track, where the wheelset and track are modelled using finite element method. The effects of elastic deformation of the wheelsets and rails on creepages, creep forces and wheel wear can be considered in the model. The investigation results indicate that the dominating order of wheel polygonal wear is 11–16, corresponding to wavelengths of 165–240 mm. The formation mechanism of high-order wheel polygonal wear is the P2 resonance of some types of track structure, and the first bending resonance of the wheelset can accelerate the development of wheel polygonal wear.