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Effects of Track Support Failures on Dynamic Response of High Speed Tracks

A model is proposed in this paper for investigating the effect of track support failures on the dynamic response of high speed tracks. In this model, the rails are modeled as two Timoshenko beams resting on discrete sleepers and interacting with a moving vehicle. The lateral, vertical and torsional deformations of the beams are all taken into account. Support failures are realized by changing the support stiffness and damping. To simulate the traveling of the vehicle along the track, the discrete supports to the rails are assumed to move backward at the train speed. Normal wheel/rail contact forces are calculated using the Hertzian contact theory and tangential (creep) wheel/rail forces are determined using Shen et al.'s nonlinear creep theory. Differential equations of the vehicle/track system are solved by means of an explicit integration method. Effects of zero to six failed supports are simulated. Numerical results indicate that track support failures greatly affect the dynamic response of a tangent track. As the number of disabled supports increases, the normal wheel/rail forces, track displacement and track acceleration increase quickly, accelerating deterioration of the track.