The role of 3D contact geometry in modeling dynamic wheel-rail interaction at short-wave irregularities on rail surface

Modelling wheel-rail interaction at short-wave irregularities is an important issue under the context of vehicle-track system dynamics for analyzing and preventing severe impact. The present paper broadens the applicability of vehicle-track dynamics model to account for 3D short-wave irregularities on rail surface. The key is developing a meshing grid approach combined with the accurate conjugate gradient (CG) method for contact mechanics under arbitrary 3D contact geometry. Therefore, both the global dynamics and local contact solutions can be provided. In this study, short-pitch rail corrugation is employed for investigating the role of 3D contact geometry in modelling dynamic wheel-rail interaction. The traditional vehicle-track coupled dynamics model using Hertzian spring is used for comparison. The results show short-pitch rail corrugation contributes two different aspects, i.e., wheel center trajectory and time-varying contact stiffness. These two aspects are found to be the root causes for explaining the influence of the varying 3D geometry irregularity size on dynamic wheel-rail contact force.