INVESTIGATION OF THE EFFECTS OF SLIDING ON WHEEL TREAD DAMAGE

摘要

Wheel tread spalling is the main source of damage to wheel treads and a primary cause for wheel removals from service. Severe frictional heating of the wheel-rail contact patch during sliding causes the formation of martensite, a hard, brittle microstructure. The martensite patches break away from the more resilient bulk of the wheel tread when subjected to contact loads, resulting in spall formation. Prolonged sliding allows a greater volume of wheel tread material to reach extremely high temperatures, which will lead to material ablation and the formation of a slid flat. Such flats are the cause of wheel impact loads, which are extremely damaging to truck components and rail. This paper outlines an approach developed to estimate the effects of sliding on wheel flat formation and the potential severity of spalling. The methodology is described and preliminary results are presented using an intentionally simplified idealization of the wheel-rail contact geometry. Material characterization (temperature-dependent properties and failure criteria) and management of model size are of equal importance to geometric fidelity and are the focus in the early stages of the development of the qualitative model present here.