Simulation and experiment based investigations of squat formation mechanisms

摘要

In this work, possible formation mechanisms of squats were investigated based on field and laboratory measurements, full-scale wheel-rail test rig experiments and a newly developed simulation tool. Wheel-rail contact conditions were found, which can lead to cracks in or to outbreaks of a white etching layer (WEL) on a rail surface. Under certain condition this also can lead to cracks growing into the bulk material. Furthermore, according to the simulation results, geometrical deviations of the rail surface - as for example outbreaks of WELs - can remain at the rail surface and grow up to a size comparable to that of squats. It has been shown, that the crack initiation potential in the area of such permanent geometrical deviations can be increased.