Coupled Vibration And Structural Noise Analysis Of Steel Plate Combined With Continuous Girder Axle

Compared with other bridges,steel plate combined with continuous girder bridge has the advantages of large span and light weight,but because of the use of large area of steel structure,the noise radiated to the space environment is wider and stronger,and the traditional sound barrier can not suppress the spread of this noise,long-term in this noise pollution environment will cause serious impact on people’s physiology and psychology.Therefore,it is of great practical significance to study the structural noise of steel plate combined with continuous girder bridges.This thesis compares the relevant assessment standards of the dynamic response and noise of the bridge at home and abroad,determines the corresponding reference specification,introduces the coupled dynamic equations of the bridge based on the coupled vibration theory of the bridge,uses ANSYS to finite element modeling of the(32+40+32)m steel plate combined with continuous girder bridge,forms a large coupled vehicle-rail-bridge model in UM,and obtains the dynamic response of the train and the bridge.Meanwhile,based on the vibroacoustic radiation theory,the FE-SEA hybrid model and the SEA statistical energy model of the steel plate combined girder bridge were developed in VA-One by combining the advantages of both the finite element method and the statistical energy method.Subsequently,the sound pressure level at each field point and the sound pressure level contribution of the radiated noise of the plate subsystem were calculated by using the results of the coupled vibration response of the bridge as boundary conditions.The study shows that: when the train passes the bridge at 180 km/h～360 km/h,all the dynamic response indexes of the train and the bridge are within the specification values;when the train crosses the bridge,the structural displacement of the bridge shows periodic changes,and the vertical acceleration at each measurement point is greater than the lateral acceleration.Simulation analysis of the acoustic model in VA-One shows that the sound pressure level of each field point decreases as the distance from the center line of the line increases;the structural noise of the bridge is attenuated in the whole frequency band,and the attenuation rate of the high frequency band is faster than that of the low frequency band;the overall structure of the bridge radiates noise,and the noise contribution is as follows: web plate > upper flange plate > top plate > lower flange plate.Exploring the influence of different factors on the bridge radiation noise found that:(1)when the speed increases,the overall sound pressure level of each field gradually becomes larger;speed from 200 km/h to 260 km/h,the rise in sound pressure level of each field is greater;therefore,control the speed of the train over the bridge can reduce the bridge radiation structure noise.(2)The overall sound pressure level increases significantly in two-way traffic,but the proportion of the contribution of each plate at the peak sound pressure level does not change significantly.(3)With plate ribs,the sound pressure level contribution of the top plate is greater than that of the upper flange plate,and the opposite is true when there are no plate ribs.The addition of plate ribs can optimize the local structure,but the overall noise reduction effect is general.The spacing between the plate ribs of this bridge should be about 5.2m.