Dynamic Research Of Track-bridge Transition Section

In recent years, with the increase of the train speed and the interactional forces between track and vehicles, the smoothness of the track has to meet higher standard .Because of the difference in stiffness between track and bridge ,the nonuniform settlement occurs easily in track-bridge transition section .The nonuniform settlement leads to the track vertical profile irregularity which has bad effects on the reliability,comfort and the amenity of high speed train.In this paper,based on the theory of vehicle-track coupling dynamics and vehicle-bridge coupling vibration,dynamic model used to simulate roadbed-bridge transition section is established.Finite element method is employed to model track and under-track basement,sleeper and blocks are simplified to mass,rails are modeled as Euler beams laid on elasticity supports, the relationship between wheel and track is determined by hertz non-linear contact theory.model of bridge and coupling effect are simulated by hertz non-linear contact theory.Time histroy integral method and iterative method by separating wheel and track are used to simulate the situation when train is passing the roadbed-bridge transition section and the conclusion about effects of train speed,settlement of roadbed-bridge transition section and length of track-bridge transition section on response of train and bridge is presented.