A finite element analysis-based study on the dynamic wheel-rail contact behaviour caused by wheel polygonization

In this study, an explicit finite element analysis method was adopted to investigate the wheel-rail impact response generated by wheel polygonization, using a three-dimensional wheel-rail rolling contact finite element model. In this model, the infrastructure below the rails and the stiffness and damping of the sleeper supports were considered. Then, the characteristics of the wheel-rail contact zone, the stress/strain state and the wheel-rail impact force of the polygonal wheel-rail system were presented and discussed and were compared with those of the ideally perfect wheel-rail system. A parametrical study was then carried out to examine the influences of train speed and the polygonal order of the wheel on the wheel-rail impact response. The finite element analysis results revealed that the vertical wheel-rail impact force induced by wheel polygonization is related to the wheel radial deviation; the maximum contact force, stress and strain are all elevated with the increase of the order of the polygonal wheel, which suggested that the wheel should be repaired when it is in the initial lower order polygonal state. These findings can provide some theoretical and technical support for the optimal design of the wheel-rail system and the safe operation of high-speed trains.