Influence of Railway Track Slab's Geometry and Dynamic Parameters on Its Sound Radiation Characteristics

摘要

Ballastless track is widely applied in high-speed railway and urban rail transit, which has high smoothness, stability, reliability, and durability. Compared with ballasted track, ballastless track produces more noise radiation. In order to probe the effect of geometry and dynamic parameters on the vibration and sound radiation characteristics of the track slab, a hybrid method of finite element method (FEM) and boundary element method (BEM) is developed. In the analysis procedure, a 3D finite element model of the slab is developed, and the vibration frequency responses of the slab under different cases are investigated. The velocity boundary conditions for the acoustic radiation model are formed by using the vibrations of the structure, and the sound radiation characteristics are calculated with the acoustic boundary element method. The numerical results indicate that the peaks of the slab's sound radiation power occur at the frequency of 230 Hz and 680 Hz, and the stable value of the slab's sound radiation efficiency is 1.0. In the dynamic response calculation, variation of length of the slab has little effect on the sound radiation power and efficiency, and thickness of the slab is inversely proportional to the value of the radiation power; the higher the stiffness and damping of CA mortar, the lower the peak value of sound radiation efficiency of the slab, and the sound radiation power also reduces significantly. Besides, the radiation acoustic field of the slab is complicated, and the variety of the parameters of the slab has great influence on the directivity of the radiation acoustic field.