Research On Vibration And Noise Characteristics Of High-speed Railway Track Structure Based On Vibration And Acoustic Combination

The areas that high-speed railways traverse are complex and diverse,and the vibration and noise impact of their operations on the surrounding environment along the line cannot be ignored.Combined with the diversified development of high-speed railways in my country,the noise sources of track structure vibration and radiation under high-speed driving conditions are also more complicated.It is particularly important to deepen the theoretical system of high-speed railway structure vibration and radiation noise.Relying on the National Natural Science Foundation of China’s "Youth Fund" project(Refined analysis of the dynamic mechanism of high-speed railway overhead line track structure based on vibration-acoustic coupling,project approval number:51708021),starting from the vibration transmission mechanism of the track structure under high-speed driving conditions,a vehicle-ballastless track-substructure vibration and noise combined analysis model is established to analyze the longitudinal and vertical vibration transmission and attenuation characteristics of the track structure in space.The spatial frequency spectrum and distribution characteristics of the vibration radiation noise in the surrounding environment is studied,and determine the spatial sensitive points of noise,study the proportion of the sound contribution of multiple sound sources near the wheel/rail area,also conduct regular analysis of the sensitive parameters affecting the environmental vibration and noise of the high-speed railway.On this basis,according to the stiffness matching of the track structure,the vibration and noise reduction effect of the track structure after the use of vibration damping pads in high-speed railways is studied.This paper has carried out in-depth research on the mechanism of environmental vibration and radiated noise induced by high-speed railways,and analyzed the effective vibration and noise reduction measures proposed.The specific research results are as follows:(1)A three-dimensional finite element model of high-speed railway vehicle track substructure is established to analyze the vibration transfer characteristics of high-speed railway track structure between different layersThe three-dimensional finite element analysis model of the vehicle-tracksubstructure in space is established by the finite element analysis software,revealing the transmission characteristics of wheel-rail coupling vibration between the various layers of the track,also between the track and the substructure,combined with field testing of high-speed railway,the vibration response obtained from the test near the axle box was verified,which laid a theoretical foundation for the establishment of combined prediction coupling model of vehicle-track-substructure of vibration and noise.(2)Clarify the spatial and spectral distribution characteristics of environmental vibration and noise of high-speed railways and the contribution of sound sourcesBased on the frequency domain analysis method,establish a high-speed railway vehicle-track-substructure vibration and noise combined analysis model.Reveal the frequency domain-spatial characteristics of vibration and radiation noise at different spatial positions of each structure in the system,and clarify the transmission characteristics of dynamic response among substructures.Analyze multiple sound sources such as structural noise caused by structural surface vibration,and extract the horizontal and vertical distribution of structural radiated noise in space.The results show that the sound pressure level of the radiated noise above the top surface of the rail in the wheel-rail area is the highest,and the noise attenuation is more significant within1.5m from the centerline of the line.The analysis of the proportion of the sound contribution of the rail,wheel,and slab shows that the contribution of the wheel radiation noise is the largest,and the contribution of the rail is the second.The sound contribution of the slab is the smallest.The proportion of each sound source changes significantly under different speed levels,and the contribution of aerodynamic noise to the sound source in the wheel-rail area cannot be ignored.(3)The influence of driving conditions and key structural parameters on the environmental vibration and noise of high-speed railways is put forwardSystematic analysis of the impact of driving speed,poor line status and track structure parameters on the environmental vibration,noise propagation and attenuation of high-speed railways,and clarifies the adverse influencing factors of environmental vibration and noise of high-speed railways and the changes in vibration and sound radiation characteristics.In general,the driving speed has a significant impact on the aerodynamic noise in the wheel-rail area.As the driving speed increases,the vibration response and radiation noise increase correspondingly.The influence of roughness and fastener stiffness on the structure is mainly concentrated in the middle and low frequency bands.The influence of fastener damping is mainly reflected in the middle and high frequency bands.(4)Based on the stiffness matching,the vibration and noise reduction control strategy of the cushion track structure is proposed.According to the feasibility of the construction and reconstruction of the highspeed railway site,this paper studies the impact of the rubber floating slab structure with the addition of vibration damping pads on the vibration and noise reduction of high-speed railways.The main frequency band for vibration and noise reduction is200～630Hz.Through the reasonable matching of track stiffness,it is recommended that the effect of comprehensive vibration reduction and noise reduction is the best when the fastener stiffness is 42 k N/mm～65k N/mm and the damping pad stiffness is0.03MPa/mm～0.05MPa/mm.