Analysis Of Vibration And Sound Radiation Characteristics Induced By Ballastless Track Of High Speed Railway Based On 2.5 Dimensional Finite Element Boundary Element Model

Based on the summary of the large number of domestic and foreign scholars' research on the vibration and noise induced by high-speed train running,a model of rail,track slab and track structure is established by using the 2.5 dimensional finite element boundary element method.The 2.5D finite element method is used to simulate the rail,track slab and track structure.The 2.5D boundary element method is used to simulate the atmosphere,The vibration characteristics and acoustic radiation characteristics of rail,track plate and track structure under unit harmonic load are discussed.The vibration and noise reduction measures are adopted.Damping rail,dynamic vibration absorbing rail,damping dynamic vibration absorbing rail,Soundproof skirt track structure and vibration damping panel track structure are established.The dynamic characteristics and acoustic radiation characteristics of the harmonic load are also analyzed.the conclusion summarizes the main research are as follows:(1)The dynamic characteristic curve show the fastener stiffness on the vibration and acoustic radiation attenuation has certain effect,and in a certain range,with the increase of the stiffness of the fastener,rail vibration and radiation sound power level decreases obviously,but the sound radiation efficiency basically unchanged.(2)The change of fastener stiffness has great influence on the radiated sound power level of rail and track structure,so the fastener stiffness should not be too small.We should try to select larger fasteners in a reasonable range.The change of elastic modulus of CA mortar layer has a certain effect on the radiated sound power level of track slab and track structure,and has a certain effect on the sound radiation efficiency of the whole track structure below1000 Hz and it has no influence after 1000 Hz.(3)The dynamic characteristic curve of the whole rail structure shows that the stiffness of the fastener has a certain effect on its vibration attenuation,and within a certain range,with the increase of fastener stiffness,the vibration characteristics of the overall structure of the track are more obvious.(4)The frequency characteristics of the radiation sound power level curve of the overall structure of the orbit are different in different frequency bands.In 772.09 before Hz,the acoustic radiated power level of rail and slab track in the whole structure of the acoustic radiated power level by accounted for respectively 11% and 89%,in the 772.09 Hz band,the acoustic radiated power level of rail and slab track in the whole structure of the acoustic radiated power level occupies respectively 68% and 32%.(5)The acoustic radiation power of the damping power absorption rail is the largest,which shows that the sound energy of the sound source is larger in the unit time.The acoustic radiation efficiency of the damping power absorption rail is the smallest.It shows that the vibration of the surface is converted into low efficiency when the structure is vibrated.(6)The attenuation rate of rail under the three measures is all higher than that of the standard rail,and the damping effect is obvious in the frequency area dominated by rail noise,and the attenuation rate is increased.(7)From the analysis of the vibration characteristics of different types of rail map: Based on dynamic vibration absorber damping dynamic vibration absorber of rail and rail compared to 60 rail in vibration attenuation in the frequency domain or trend can be seen in the rail vibration attenuation has played a larger role,but from the production process and the effect of vibration reduction and installation considerations the dynamic vibration absorbing type rail is more suitable as the most effective measures to reduce vibration of rail.(8)The results of the 2.5D finite element boundary element method show that the structure of the vibration reduction panel track has a good damping effect on track structure vibration,but the effect of noise reduction on track structure is very poor.The track structure of soundproof skirt has very poor effect on track structure vibration,but it has a very good effect on noise reduction of track structure.It has strong feasibility in high-speed railway,and has obvious effect on reducing the radiation noise of high-speed railway track structure.