Simulation And Analysis Of Pass-by Vehicle Noise Based On Transfer Characteristic

With reference to standard test requirements for pass-by noise(PBN),the representative air noise signal of the vehicle is taken as the point of penetration.Frequency Response Functions(FRF)at the signal acquisition point from the discrete positions on the vehicle driving path,by taking the noise source signal obtained from test as an incentive,based on the sound source transmission characteristics.The PBN when vehicle run to each position is simulated.In order to simulate the PBN in the whole time domain,the PBN from each position is processed with the Maximum Entropy Spectral Estimation(MEM),to get the power spectrum of the vehicle noise.The simulation result is contrasted with the outdoor test data.The vehicle PBN in domain is analyzed with the power spectrum.According to the characteristics of noise transfer function,the noise sources of vehicles are made up of the structure acoustic effect and the air sound effect,PBN is the performance of vehicle structure vibration together with the airflow noise.The distribution law of the vibration noise signal on the wide band is analyzed,and the air source is selected as the main noise source.In accordance with the indoor PBN test configuration,with exhaust noise as the noise source representative,to arrange a series of discrete microphones as the acoustic response positions in the left of vehicle path direction.The ideal semi-free field acoustic space is created.For the convenience of calculation,the source and receivers are exchanged.The fast multi-pole boundary element method is used to calculate the FRF.The exhaust noise data is segmented to input into each source in the model to solve the response signals.The noise signal of the exhaust noise from a certain type of vehicle is segmented in time domain,and the response of time domain signal in each position is calculated by convolution calculation.The response of each point are output to the MATLAB.The MESM program is composed,from which the whole PBN spectrum is output by taking response as input.The output of the program is the power spectrum of the whole noise.The frequency spectrum obtained by the power spectrum.By using A weighted network filter,the PBN is simulated by inverse Fourier transform to the spectrum.Combining the performance of the final simulation in the time domain and the frequency domain,the PBN is analyzed.