Subsurface rolling contact fatigue damage of railway wheels - A probabilistic analysis

摘要

A numerical model for predicting the probability of subsurface initiated rolling contact fatigue failure in railway wheels subjected to operational loading is presented. The loading is evaluated through simulations of dynamic train-track interaction incorporating the influence of, e.g., corrugation. Contact stresses are found from Hertzian theory and the resulting stress field from theory of elasticity. Fatigue damage is evaluated by use of a Wbhler curve where the fatigue strength is decreased due to the influence of material defects, which are presumed to be of random size and occurrence in the stressed volume of the wheel rim. Damage accumulation is performed using the Palmgren-Miner rule, extending the model to cases of variable loading. The results show how a combination of rail corrugation and high train speeds have a significant impact on the probability of fatigue failure. A sensitivity analysis reveals a strong influence of the fatigue strength and the material defect distribution on the probability of fatigue failure.