An experimental and numerical study on the generation of wheel-rail stick–slip contact behaviour

Stick–slip is considered the root cause of railway engineering phenomena such as squeal noise and corrugation. Little consensus regarding the actual physical description of stick–slip has been achieved because its manifestations cannot be explained by a single underlying mechanism. To investigate the generation mechanisms of stick–slip contact, this study reproduced wheel-rail stick–slip experimentally with an in-house test rig—V-Track and numerically with an explicit finite element method (FEM). The V-Track is capable of reproducing realistic wheel-rail dynamic interactions under well-controlled lab conditions, while the explicit FEM has been proven to be suitable for the simulation of dynamic contact and frictional instability. Crucial influential factors including wheel-rail lateral creepage, friction levels, and friction characteristics were varied in the experiments and simulations to examine their impacts on the occurrence of stick–slip. The study shows that the creepage level needs to be sufficiently high to generate stick–slip. Stick–slip can be eliminated by reducing friction to a very low level, whereas changing the friction characteristics from negative to positive may not work for stick–slip mitigation. Moreover, wheel-rail friction conditions cannot be sufficiently represented by a single parameter, i.e. coefficient of friction.