Vertical dynamic vehicle-track interaction in a railway crossing predicted by moving Green's functions

A versatile and computationally efficient method for simulation of high-frequency dynamic vehicle-track interaction in a railway crossing is presented. The track model is based on a linear, time-invariant and non-periodic finite element model of a railway turnout accounting for variations in rail cross-sections and sleeper lengths, and including baseplates and resilient elements. To account for the longitudinal motion of the wheel, a set of moving Green's functions is pre-calculated to represent the dynamics of the crossing. The lateral position of the wheel centre (but not the contact positions on wheel and rail) is prescribed and could be determined by a previous simulation of dynamic vehicle-track interaction using a multibody dynamics software. The vehicle model includes one half of a wheelset and the primary suspension. In each time-step of the simulation, the three-dimensional surface geometry of crossing and wheel is described by four-noded linear elements. Vertical non-Hertzian (potentially multiple) wheel-rail contact is solved by an implementation of Kalker's variational method CONTACT. The method is demonstrated by calculating the impact load and wheel-rail contact stress distribution for the case with a nominal S1002 wheel profile passing over a nominal crossing geometry.