Predictions Of Wheel/Rail Vibration And Noise For High-speed Railway Slab Tracks

Railway noise pollution has be attracted much attention with the rapid development of high-speed railway.As one of the main source of railway noise,the prediction of wheel/rail noise should be further studied.In this dissertation,the research objects are the high-speed train wheel and high-speed railway track.The vibration and sound radiation prediction model of a train wheel is established by considering its symmetry and rotation effect.The vibration and sound radiation prediction model of a railway track is established by considering its infinite,periodic and moving wheel/rail force.Finally,the wheel/rail vibration noise prediction model is established by considering the high-frequency wheel/rail interaction and the excitation of wheel/rail roughness spectrum.The research work and main conclutions in this dissertation are summarized as follows:(1)The vibration sound radiation prediction model of a fast rotating train wheel is established by using 2.5D finite element method(2.5D FEM)and the 2.5D acoustic boundary element method(2.5D BEM).The 2.5D FEM,2.5D BEM and relevant programs are validated by comparing vibration and sound radiation results of the wheel from this procedure with those from commercial software.Then,the effects of wheel rotation speed on wheel vibration and sound radiation are discussed by utilizing the established model.The results show that wheel rotation splits most peaks of the vertical displacement mobility at the wheel/rail contact point,the sound pressure level at a pre-defined standard point and radiated sound power level into two peaks,and the bigger the wheel rotation speed is and the higher the frequency is,the greater the splitting of the peak is.The wheel rotation speed also has important influence on directivity of the radiation,and contribution of each part of the wheel.Therefore,the rotation effect of a high-speed rotating train wheel should be taken into account when calculating its high-frequency vibration and sound radiation.(2)The vibration prediction model of a slab on the elastic foundation is established by superposition method based on the thin plate theory.The commercial software was used to verify the validity of the vibration and sound radiation prediction model of the track,which is established by the hybrid method based on Fourier transform,2.5D BEM and Rayleigh integral formula.The influences of the wheel/rail force moving speed on vibration and sound radiation of the track are discussed by using the validated model.The results show that the moving speed of wheel/rail force has important influence on the vibration and sound radiation of the rail and slab.Therefore,the move of wheel/rail force should be taken into account when calculating the high-frequency vibration and sound radiation of a track subject to high-speed moving wheel/rail force.(3)The wheel/rail force under the measured wheel/rail roughness spectrum is calculated by utilizing the excitation model of moving roughness spectrum.Furthermore,the wheel/rail vibration noise prediction model is established.The wheel/rail vibration noise prediction model is used to compare the vibration response and noise radiation of the wheel,rail and slab,respectively.The influences of the wheel rotation,train speed,wheel structure parameter and track structure parameters on the wheel/rail vibration and sound radiation under the measured wheel/rail roughness spectrum are also discussed.The results show that the wheel/rail overall noise and wheel overall noise will be underestimated,while the rail overall noise and slab overall noise will be overestimated if the wheel rotation is neglected.The vibration and noise of the wheel,rail and slab are increase along with the increasing speed of train,and speed of noise raising that is from fast to slow is wheel,rail and slab.The noise contribution to the standard point C that is from big to small are wheel noise,rail noise,and slab noise.(4)High-speed Wheel-Track Interaction Noise Software(HWTINS)is developed by using Matlab programs.