ANALYSIS OF DYNAMIC BEHAVIOR FOR BALLASTLESS TRACK-BRIDGE WITH A HYBRID METHOD

摘要

A hybrid method combining finite element method (FEM) and statistical energy analysis (SEA) was recently presented for predicting the steady-state response of vibro-acoustic systems. Based on the structural characteristics of vehicle-CRTS Ⅱ ballastless track-bridge system, the hybrid method of vehicle-track-bridge elements was presented. Using finite element method and Hamilton Theory, the coupled equation of vehicle-track-bridge can be established. Computational software is coded with Matlab. As an application, the vibration characteristics of the track-bridge system vertical profile assumed as random irregularity were calculated and the effect of random irregularity wavelength was analyzed. The computational results show that (1) The changes of the rail random irregularity wavelength have little influences on vertical displacement of track structure. (2) While it has very significant influences on vertical wheel/rail contact forces, and vertical acceleration amplitude of rail and slab, and the influences caused by rail short-wave random irregularity are greater, and it has influences on vertical acceleration amplitude of bridge. (3) The energy of rail vibration excitated by rail short-wave random irregularity is mainly distributed within the range of medium-high frequency and the maximum distribution in the range of the first natural frequency (1236 Hz) of rail. While the energy of rail vibration excitated by rail medium-long wave random irregularity is mainly distributed within the range of medium-low frequency.