Research On Low-frequency Vibration And Noise Reduction Technology Based On Dynamic Vibration Absorber

High-speed trains have developed rapidly in recent years,because of its high speed,convenience,low rate of delay and other advantages,more and more people began to take the high-speed train as the first choice for travel.The noise which comes along with the development of high-speed train not only affects the health of drivers and crew,but also restricts the development of high-speed train.The problem of low frequency noise in high speed train is outstanding,and the control of low frequency noise has not achieved good results.In this paper,the dynamic vibration absorber is applied to the interior structure of the car body,and the low frequency noise is controlled by improving the transmission loss of the interior panel.First of all,the vibration and noise inside the EMU are tested.The analysis found that the problem of the middle and low frequency noise in the vehicle is outstanding,it appears single peak noise at the band which has larger energy in the low frequency.The single-frequency noise and the single-frequency vibration on the interior trim panel of the vehicle have a great relevance.The corresponding single-frequency vibration can be controlled by installing a dynamic vibration absorber on the trim panel,this could reduce the sound radiation of the plate,so that the prominent single-frequency noise could be controlled and the low frequency noise of the vehicle could be improved to a certain extent.Based on the analysis results,the frequency range of the dynamic vibration absorber is determined.Then,the main system-sheet structure on which the dynamic vibration absorber is installed is studied.The theory and simulation analysis are made from the aspects of natural frequency,mode shape,sound radiation and sound transmission loss.Finally,the principle and design method of the dynamic vibration absorber are described,and a dynamic vibration absorber with continuous stiffness is designed for the thin plate structure.The dynamic vibration absorber is made up of four vibrators,which has small mass and a high dynamic-static ratio.Sound insulation experiment is done with using assembled dynamic vibration absorber.The experimental results show that the dynamic vibration absorber can effectively reduce the vibration of the thin plate in the designed frequency range,and improve the sound insulation performance of the thin plate obviously,so the dynamic vibration absorber has obvious effect of reducing vibration and noise.It has established the experimental foundation for the application of the dynamic vibration absorber in the EMU.