Effect of the first two wheelset bending modes on wheel-rail contact behavior

The objective of this paper is to develop a new wheel-rail contact model, which is suitable for considering the effect of wheelset bending deformation on wheel-rail contact behavior at high speeds. Dummies of the two half rigid wheelset are introduced to describe the spacial positions of the wheels of the deformed wheelset. In modeling the flexible wheelset, the first two wheelset bending modes are considered. Based on the modal synthesis method, these mode values of the wheelset axle are used to solve the motion equations of the flexible wheelset axle modeled as an Euler-Bernoulli beam. The wheel is assumed to be rigid and always perpendicular to the deformed axle at the wheel centre. In the vehicle model, two bogies and one car body are modeled as lumped masses. Spring-damper elements are adopted to model the primary and secondary suspension systems. The ballasted track is modeled as a triple layer discrete elastic supported model. Two high-speed vehicle-track models, one considering rigid wheelset models and the other considering flexible wheelset models, are used to analyze the differences of the numerical results of the two models in both frequency and time domains. In the simulation, a random high-speed railway track irregularity is used as wheel-rail excitations. Wheel-rail forces are calculated and analyzed in the time and frequency domains. The results clarify that this new contact model can characterize very well the influence of the first two bending modes of the wheelset on contact behavior.