Vibration And Noise Reduction Characteristics Of Damped Rail

With the rapid development of rail transit in China and the improvement of train running speed,the problems of noise control and vibration of passenger trains are becoming more and more prominent.Rail noise is the main source of railway noise,and the suppression of rail vibration noise is an important goal of railway vibration reduction and noise reduction.It is found that damping rail is one of the most efficient methods.This article from the perspective of rail vibration and acoustic characteristics,combined with finite element method and based on the acoustic radiation theory of boundary element method,The model of standard rail,constrained damping rail and dynamic vibration absorber rail is established,and carries on the modal analysis and harmonic response analysis,dynamic response analysis and analysis of sound radiation characteristic,discussed its anti-vibration noise reduction effect.The main research contents and conclusions are as follows:(1)The modal analysis results show that the modal modes of the constrained damped rail model are basically the same as those of the standard rail model,and the natural frequency and maximum vibration displacement of the rail with the constrained damped rail are smaller than those of the standard rail model.In harmonic response analysis,with the increase of the thickness of the damping layer at the top and waist of the rail,the response peak gradually decreases,indicating that the damping effect becomes better and better with the increase of the thickness of the damping layer.The vibration displacement response of the constrained damped rail and the dynamic vibration absorber rail at the peak is much lower than that of the standard rail,and the dynamic vibration absorber rail displacement value is the lowest,indicating that the dynamic vibration absorber has the best vibration reduction effect.(2)the dynamic analysis results show that the vertical displacement of the four nodes on the rail roof is symmetrical about the central axis.At the central axis,its displacement value is the largest,and then gradually decreases to both sides.Under the same speed and constrained damping layer,the rail vertical displacement of the dynamic vibration absorber which is used to value lower than the standard rail,and rail top vertical vibration displacement values higher than the rail waist place,constrained damping,vibration dynamic vibration absorber which is used the best effect,with the movement speed increase of moving load,the waist place of the rail head and rail vertical vibration displacement values are increased obviously,but the displacement value reduction is gradually reduced.(3)the results show that the acoustic radiation properties,the standard rail,constraints,the rail acoustic radiation damping and dynamic vibration absorber which is used to power have similar variation trend,rail noise is the dominant frequency band 500-2500 hz,in less than 600 hz frequency range,the basic dynamic vibration absorber which is used without damping effect,above 600 hz frequency range,the dynamic vibration absorber which is used to the noise reduction effect is best,followed by multiple constraint damping,finally the monolayer constrained damping steel rail.The directivity analysis of the radiation noise of different types of rails shows that the radiation noise of the middle and low frequency rails from 10 Hz to 1010 Hz is more directivity,and the main energy is transmitted along both sides of the rails.