Research On Simulation Methods Of Full-band Noise In High-Speed Train

Recent years,China's high-speed railway enterprise has made considerable progress and success.However,the light-weight vehicle body and the continuous improvement of operating speed have increased the difficulty of vehicle interior noise control.Conventionally,we could test its acoustic performance using sound source identification and OTPA analysis after the vehicle prototype was manufactured,which has been proved to be effective in the short term.However,carrying out real test of high speed train is time-consuming,also,the consumption of manpower and material resources could never be ignored.Thus,in view of production efficiency,real line test for high speed train is inefficient in the long period.Therefore,if we could carry out the acoustic design and improvement of vehicle acoustic performance in the R&D stage before production and manufacture,that would greatly improve production efficiency as well as save manpower and material resources.Therefore,it is very important to study the simulation methods of acoustic performance in the train.This paper represent an improved experimental statistical energy method based on power flow analysis for interior noise simulation in high speed train after a comprehensive investigation of the existing simulation methods for interior noise simulation,and verify its validity after a calculation of the interior noise in high speed train of a frequency-band of 100-4000Hz according to the real line test datas.Firstly,we carried out a statistic experiment of the high speed train,obtained its acoustic parameters such as the sound insulation and sound absorption coefficient;through a real line test of high-speed train,obtained the noise and viberation acceleration inside and outside the train at the speed of 350km/h,which acted as the excitations in the later interior noise simulation.Secondly,based on the statistical energy analysis method,obtained the damping ratios and damping loss factors of profiles used in the train including the outfloor,sidewall and roof etc,using the free decay method;through a series of simulation experiments,calculated modal densities of the profiles used in the train and coupling loss factor between different subsystems,as the basic simulation parameters for the next step of the interior noise simulation.Then,according to the manufacture 2D engineering drawings,established the simulation geometric model and finite element model,and divided the model into different subsystems.Then,carried out a simulation of interior noise in high speed train with a pantograph to verify the validity and reliability of the method.Finally,based on the theory of power flow,analysed the contribution of the interior noise in high speed train.