Wheel tread profile evolution for combined block braking and wheel-rail contact - Results from dynamometer experiments

Paper in proceeding, 2015

Wheel treads are subject to different types of damage such as wear, rolling contact fatigue (RCF), thermal cracks, plastic deformation and also flats caused by wheel sliding. Some of these phenomena is followed by a change in tread profile which results in frequent wheel reprofiling to keep rich comfort of the vehicle. In this study, a series of full-scale tread braking experiments, including wheel-rail rolling contact, were conducted in order to clarify the influencing factors of evolution of wheel tread profile. The experiments focused on plastic deformation and wear caused by rolling contact and tread braking. The presented results show that the maximum tread depression is 0.20 mm at the rolling contact center after 40 times stop braking actions. This is considered to be caused by plastic deformation of the wheel tread induced by high contact pressure and material softening due to high temperatures from tread braking. This result is supported by the observed protrusion of the tread near the rolling contact area and also by a difference of hardness between the rolling contact area and other tread area.