The Analysis And Controll Of Vibration And Accoustic Radiation Of The Rail

With the increase of train velocity,the vibration and the noise of the track are increasing.It is important to reduce vibration and noise when designing the track.In this paper,a discrete track model is established.From this model, the receptance to the incentive position can be given.The length of the track in ANSYS is 39m according to vibrating decay rate.The finite element model of the track is established in ANSYS.It includes the rail, the pad, the sleeper, and the ballast.The receptance to the incentive position can be gotten from the finite-element model as the length of the rail element SOLID45 is 0.03m, 0.05m and 0.1m respectively.By contrast with the receptance above,result is the best when the length is 0.05m.At the same time, the calculation is not too complicated.The receptance of the nodes on the surface of the rail can be gotton under the core frequencies of 1/3 octave frequcncy band between 50 and 4000Hz.The boundary-element model of the track can be established in SYSNOISE by importing the grids of the rail surface in ANSYS.Through importing the displacement of the nodes on the rail surface gotton from ANSYS into SYSNOISE and treating it as boundary conditions of displacement, the rail acoustic radiation efficiency and the rail noise power are given.The rail acoustic radiation efficiency is approximately proportional to the frequency between 50Hz and 800Hz and has concussion between 1000Hz and 4000Hz.The rail acoustic radiation efficiency has little difference whether the force is on the sleeper or in the middle of the sleeper.The rail noise power can be given by MATLAB programme using displacement and the rail acoustic radiation efficiency from ANSYS and SYSNOISE respectively.By contrast with the rail noise power gotten from SYSNOISE,the MATLAB programme is found correct.It provides a theoretical foundation for getting the rail noise power from the rail vibration directly and simplifies the calculating process.Through analyzing the changes of the rail-wheel force and the rail vibration and noise under the influence of adding constrained damping layer and changing the stiffness and the damping value of the pad,three measures are found to effectively reduce the vibration and the noise of the rail.They are increasing the stiffness and the damping value of the pad and adding constrained damping layer on the rail.