| With the rapid development of high-speed railways,the interaction force between wheel and rail continues to strengthen,and the contact relationship between wheel and rail continues to deteriorate,resulting in more and more serious noise pollution caused by wheel-rail vibration.Ballastless tracks have been widely used in high-speed railways because of their high smoothness,high comfort,and low maintenance.However,the noise pollution generated by ballastless track is far greater than that of traditional ballast track.Therefore,studying the vibration and sound radiation characteristics of ballastless track at high frequencies provides a certain theory guide for formulating vibration reduction and noise reduction measures for ballastless track.The specific research contents and research results are as follows:(1)Based on the actual vehicle dynamic parameters,a rigid-flexible coupling dynamic model of the vehicle-rail is established,and the key components in it are flexibly processed,including the wheelset,the rail and the foundation under the rail.The measured data validates the kinetic model.(2)Establish a finite element model of CRTSII ballastless track,use the finite element model to study the vibration response of the track system at high frequencies,and obtain the vibration response of the track system in the frequency domain under the unit harmonic load through the harmonic response analysis.The transient analysis obtained the vibration response of the track system under the train load.The research shows that the rail system is mainly dominated by the first-order bending vibration and pinned-pinned resonance of the rail within 2000 Hz.The rail and track plate attenuate faster along the longitudinal direction at 0～960Hz,the rail decays slowly along the vertical direction,and the track plate decays faster along the vertical direction.Through the time domain analysis,it is found that the rail is mainly vibrated by the top of the rail,the rail plate is mainly vibrated on the plate,and the rail vibration is larger than that of the rail plate.(3)Establish the boundary element model of the CRTSII ballastless track,use the boundary element model to analyze the radiation noise of the track system in the timefrequency domain,and obtain the sound pressure distribution in the near field of the track plate through the time domain analysis.It can be seen from the process of the bogie passing through the rail.Through the frequency domain analysis,it can be obtained that the noise energy of the rail is mainly concentrated in the range of 2000 Hz,and as the frequency increases,the sound radiation power first increases and then decreases,reaching maximum value at the pinned-pinned resonance frequency.By calculating the sound radiation power and sound pressure of the rail and the track slab respectively,it is concluded that the noise radiated by the rail is greater than that of the track slab.(4)Using the finite element-boundary element method,the wavelength,wave depth,wave depth of the wheel polygon and the train running speed on the vibration and noise of the rail system are studied respectively.The research results show that the shorter the wavelength of the rail corrugation,the stronger the vibration of the rail system and the greater the total sound radiation power.When the wave depth is 10μm～20μm,the vibration acceleration of the rail and the track plate increases linearly with the wave depth,and the larger the wave depth,the greater the total sound radiation power.When the running speed of the train is between 250km/h and 350km/h,the vibration acceleration of the rail and the track plate increases rapidly.The greater the speed,the greater the total sound radiation power. |
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