Research On Vehicle-bridge Coupling Vibration And Structural Noise Of High-speed Railway

In recent years,the development of China’s rail transit has been extremely rapid.The development of high-speed railways has reached the world-leading level and has become an important business card for China’s modernization.As the speed of highspeed trains continues to accelerate,the problems of vibration and noise of bridge structures caused by them have become increasingly prominent.As a kind of lowfrequency noise,bridge structure noise has a long propagation distance and slow attenuation speed,which has an impact on human health.Therefore,studying the vibration of bridge structures and exploring the mechanism and distribution of structural noise have important engineering applications and theoretical values.Based on the comparison of domestic and foreign vehicle and bridge dynamic performance and low-frequency noise evaluation standards,this paper determines the reference specifications,and introduces the vehicle-rail-bridge coupled dynamic equation and the infinite-field boundary element integral equation of sound field for sound pressure level solution.Based on the combination of finite element and boundary element theory,the calculation process of structural acoustic radiation based on the vehicle-rail-bridge coupling theory is given.Taking the 24m simple-supported box girder as the research object,a 31-degreeof-freedom vehicle model was used for vehicle-bridge coupling dynamic analysis.The vibration mode and natural frequency of the bridge are listed,and the dynamic trends of the vehicle and bridge dynamic indexes at different speeds are analyzed to obtain the vertical wheel-rail forces under track irregularities.Then the finite element and boundary element method is used to establish the sound field analysis model of the bridge structure.The vertical wheel-rail force is used as the excitation,and the dynamic response of the bridge structure is used as the boundary condition to analyze the sound pressure level of the structure.Research shows that when a train passes a simply-supported beam bridge at high speed,the bridge displacement exhibits periodic fluctuations.As the vehicle speed increases,the dynamic parameters of the bridge and the vehicle increase to varying degrees.The maximum noise of the bridge structure is located near the loading of the train.The sound energy is radiated from the bridge structure to the external space,and its frequency band is mainly below 100 Hz,which is distributed directly above and below the bridge structure.Noise is attenuating during the propagation process and attenuates as the propagation distance increases.On this basis,this article further analyzes the influence of parameter changes on bridge noise,and the results show that as the train speed increases,the noise sound pressure level increases non-linearly,and reasonable control of the speed of travel can reduce the structure’s vibration and noise radiation.The change of the plate thickness of the bridge section can affect the noise pressure level.As the plate thickness increases,the noise pressure level decreases.Different plates have different effects on the sound pressure level.At the same time,the change in the stiffness of the bridge structure will affect the vibration response and then the sound pressure level distribution.The greater the stiffness,the smaller the sound field noise level.