Numerical study on local wheel temperature induced by wheel flat during tread braking

Defects on the wheel tread, e.g. wheel flat, change the wheel‒brake shoe contact during tread braking. The local temperature can rise to a higher level than the bulk temperature, which increases the risk of martensite formation. However, there is no simulation approach that can reconcile the computation speed and accuracy with the occurrence of wheel surface defects. Focusing on the local wheel temperature, an efficient finite element simulation procedure including a wheel‒brake shoe contact model and a heat transfer model is developed. A non-uniform heat flux density reconstruction method is proposed as a bridge to overcome the incompatibility of mesh size and time step. The temperature of a wheel with a flat is investigated in detail, considering the effects of pile-up edge, initial speed and braking force on the maximum wheel temperature. Important results include that the pile-up edge of the wheel flat and the initial speed increase the maximum wheel temperature to a level beyond the austenite transformation criterion, while the braking force has only a small effect. • An effective method for non-uniform wheel-brake shoe heat flux is proposed. • Local temperature induced by wheel surface defect during tread brake is simulated. • Effect of wheel flat and brake parameters on wheel temperature is investigated.