Research On Vibration And Noise Of Elevated Track Structure Based On Hybrid FE-SEA Method

With the rapid development of urban rail transit and the enhancement of people’s awareness of environmental protection,the structural vibration and noise of elevated rail bridges have become a bottleneck restricting the development of elevated rails.Therefore,studying the vibration and noise characteristics of elevated rail bridge structures under train loads is of great significance to promoting the development of rail transit and improving people’s living standards.This paper takes the Shanghai-Kunming high-speed railway super large box girder bridge as the engineering background to carry out the research on the vibration and noise prediction method of the elevated track structure.The main research contents and conclusions are as follows:(1)Through reading a series of research results of domestic and foreign scholars,the research status and progress of environmental vibration and noise induced by elevated rail transit are reviewed,and the theory,model and prediction method of vibration and noise of elevated rail bridge structure are discussed.Research on field test of vibration and noise of elevated track bridge structure,and discusses the research method of obtaining statistical energy parameters.(2)The vehicle-induced vibration and radiation noise of the box girder bridge were measured by field tests on the super large box girder section of the Shanghai-Kunming high-speed railway.The test results show that the vibration law of each plate is generally consistent.The peak frequency of vibration of the far rail web,top plate,near rail web,and bottom plate at the support section are all 125 Hz,and the top plate has the largest vibration level,about 100 d B,the vibration level of the far-orbit web is the smallest,about 90 d B;the peak frequencies of the box girder near-orbit wing,near-orbit web,far-orbit web,and far-orbit wing are all: 31.5Hz and 125 Hz.The vibration peak frequency range of the top and bottom plates is 80～125Hz,and the peak frequency range of the bottom plate is 63～160Hz;the structural noise of the box beam is mainly concentrated in the frequency range of50Hz-200 Hz,and the peak frequency of the structural noise near the bottom of the box beam is 80 Hz.(3)The basic principles of the hybrid FE-SEA method based on wave theory are introduced in detail.It mainly includes the application characteristics of the hybrid method,and introduces the derivation process of the hybrid method from three aspects: the division of subsystems,the derivation of FE subsystem displacement response and the derivation of SEA subsystem response.(4)Based on the basic theory of the vehicle-rail coupling model and the hybrid FE-SEA method,use the large-scale commercial software VAone to build the elevated track box girder model;use UM to build the vehicle model and calculate the wheel-rail force.And test the typical structure of the elevated track to obtain key statistical energy parameters.Part of the field points are selected to calculate the box girder structure noise,and the numerical calculation results are compared with the actual measurement results.The results show that the model can accurately predict the box girder structure noise and improve the calculation efficiency.(5)Using the verified hybrid model,analyze the structural radiation noise characteristics and sound contribution of each sub-system of the box girder(top plate,bottom plate,near-orbit wing plate,near-orbit web,far-orbit wing,and far-orbit web)And analyze the influence of the thickness of each panel of the box girder and the train speed on the structure noise of the box girder.The results show that the sound contribution of the box girder top plate and the near-orbit wing plate is greater,accounting for 76.72% of the overall sound pressure level.The thickness of the box girder top plate has the greatest impact on the noise of the box girder structure,and within a certain range,as the vehicle speed increases,the noise of the box girder structure increases.