Wheel Wear Analysis of Metro Vehicles with Asymmetric Braking Force

Air braking is widely used in metro vehicles. As a result of manufacturing errors and braking failures, uneven brake pad forces often occur on the left and right sides during the braking process of metro vehicles. To investigate the effect of uneven brake shoe pressure on wheel wear in metro vehicles and thereby enhance braking safety, a dynamic model of a metro vehicle considering brake shoe braking was established. The Jendel wear model was adopted to study the wheel wear response of metro vehicles under uneven brake shoe pressure conditions, targeting different complex fault operating scenarios. The results show that under the straight-line condition, the lateral displacement, yaw angle, lateral force, and wheel wear increase with the uneven degree of brake shoe pressure. On the right curved track, the brake failure of the inner wheel increases these indicators, and the brake failure of the outer wheel decreases these indicators. When the failure is complete, the inner side fault increases the wheel wear by 19.53%, and the outer side fault reduces it by 46.39%. The lack of braking force on the inner side of the curved track is not conducive to train operation, while the lack of braking force on the outer side of the curved track has no significant negative effect on train operation. Moreover, the wheel wear will increase under the unbalanced braking coupled with the wheel diameter difference. The research contributes to the optimization of metro vehicle braking systems and the operation and maintenance of wheel-rail systems.