Recognition Technology Research Of Main Acoustic Radiation Point In Subway Train Based On NAH Technology

Near-field acoustic holography(NAH)has an important role in the study of vibration and noise radiation characteristics,noise source identification and location.It helps to control the vibration and noise of the structure,and it has a high application value in engineering.This paper briefly introduces the background and significance of the research.It introduces the concrete algorithm principle and the realization process,and studying the errors in the reconstruction process and proposing solutions.The algorithm of sound field reconstruction is written and the relevant engineering application is carried out.In this paper,the reconstruction error in the process of sound field reconstruction is studied.In the reconstruction process due to the finite effect of aperture caused by the reconstruction error,the window function joins the practice to solve the problem.The experimental results show that the window function can effectively reduce the spectral energy leakage and make the sound pressure value of the holographic aperture edge region smooth transition to zero value,which can effectively identify the sound source.For the exponential amplification of the inverse transfer factor in the reconstruction process of the sound field,the filter composed of Harris cosine window is used to suppress the amplification of the noise error in the high wave number region and obtain the optimal accuracy by selecting the appropriate cutoff wave number to ensure the reconstruction precision.Based on the basic principle of planar NAH technology,the preparation of sound field reconstruction program is carried out,and the relevant verification is carried out in the anechoic laboratory and reverberation room,which proves the feasibility of the algorithm.Finally,the plane side wall of the subway train under different operating conditions is scanned by plane NAH technique.The experimental data are analyzed and processed by the algorithm,and the acoustic radiation of the whole side wall is obtained.This provides the basis for the follow-up subway train vibration and noise reduction.