Study On Acoustic And Vibration Characteristic Of Vibration Reduction Double-block Ballastless Track

When we enjoy the convenience that railway traffic brings our life,we also put forward higher requirements for railway traffic vibration and noise,which forces us to spend more efforts in the study of vibration and acoustic radiation of railway.Widely used vibration reduction double-block ballastless track has better damping property,Based on the research results of the vibration and acoustic radiation of the track system at home and abroad,In order to research frequency-domain properties of vibration attenuation and acoustic radiation,the main research contents and achievements are as follows:1?Based on the understanding of the models and methods of the vibration and sound radiation at home and abroad,the vibration mechanics model and acoustic boundary element model were established under the reasonable boundary conditions and load.And the finite element method and boundary element method are used to study the steady-state vibration and acoustic radiation characteristics of three-dimensional complex structures under external force.2?Through the calculation model of vibration sound radiation,this paper analyzes the attenuation law of the longitudinal and vertical vibration and the acoustic radiation distribution characteristics of each layer in the structure of the double block ballastless track under the action of the unit harmonic excitation,studying the influence of the rail pad and the damping layer on the vibration reduction performance of track structure.Then based on the panel acoustic contribution analysis theory,the rail is divided into several parts and the position and degree of the acoustic radiation are quickly located,which maybe can provide a solution for reducing rail noise.3?The rail pad is the link between the rail and the substructure.The variation of the support stiffness of the rail pad affects the coupling between the rail and the substructure,and the variation of the damping of the rail pad affects the transmission of the vibration energy between the rail and the substructure and the energy dissipation,based on the established numerical model,the paper studies the influence of the change of the rail padsupport parameters on the vibration and acoustic radiation of the structure layers of track and the influence frequency band.4?the damping layer is the link between the slab and the support layer.The variation of the support stiffness of the damping layer affects the coupling between slab and support layer,and the variation of the damping of the damping layer affects the transmission of the vibration energy between the slab and the support layer and the energy dissipation,based on the established numerical model,the paper studies the influence of the change of the damping layer support parameters on the vibration and acoustic radiation of the structure layers of track and the influence frequency band.This paper vercomes the shortcomings of the previous analysis of the acoustic vibration system,studying on the vibration and acoustic radiation characteristics of track structure from the perspective of the whole system.It may provide reference for the design of vibration and acoustic reduction track and setting reasonable parameters of corresponding frequency bands.