Theoretical And Experimental Study On Patch Near-field Acoustic Holography Based The Distributed Source Boundary Point Method

Near-field acoustic holography (NAH) built on the acoustic radiation is an important technology for identifying noise sources and visualizing acoustic field. It is of significance for controlling noise sources effectively and researching acoustic radiation characteristics; it can provide plentiful information of sound source and sound field for actual noise and vibration analysis. While Patch Near-field Acoustic Holography (PNAH) is a new near-field acoustic holography.In this paper, the research status and development trends of PNAH are described, and PNAH based on the distributed source boundary point method (DSBPM) is proposed. The model of PNAH based on the DSBPM is also established; then the reconstructed result obtains from the data of extrapolation. During the reconstruction procedure, the reconstruction errors is suppressed by using a reasonable regularization method. The simulation results show that this method has good result on the condition of the small holographic aperture; then experiments further verify the correctness of the proposed method.In chapter one, the trend of NAH is analyzed. After a simple of this method, the current status of the existing four kinds of PNAH and their relative merits are studied. To these problems, the main research content and meaning are introduced in the dissertation.In chapter two, the algorithm of the DSBPM is introduced. Considering the high sensitivity of the reconstructed results to the measurement errors , the Tikhonov regularization method is proposed to stabilize the reconstruction procedure and restrict the influence of errors.In chapter three, PNAH based on the DSBPM is proposed after analyzing NAH based on the DSBPM. The near-field extrapolation model of PNAH based on the DSBPM is also established. Then a simulation analysis of pulsating sphere is studied.In chapter four, the method is used in the experiment of a clamped point-driven steel plate. The experimental results show that the method can provide good reconstructed result on the condition of the small holographic aperture. While the experimental results to a speaker of the different frequency show good applicability of this method.In chapter five, the researches in this dissertation are summarized, and some topics for further study are given.