Research On The Acoustic Holography Measurement Method For Impedance Characteristics Of Planer Array

The radiation impedance characteristic of transducer array is one of its important performance indicators.How to determine the radiation impedance of transducer array quickly and accurately has become a hot topic.The numerical calculation method can be used to analyze the impedance characteristics of the array,but this only has a guiding role in the initial stage of transducer design.In practical applications,however,there is a certain deviation between the actual radiation impedance characteristics and the simulation results.Therefore,the research on the measurement method of the array radiation impedance characteristics is very important for the development of the transducer array.Near-field acoustic holography(NAH)technology is an effective noise source identification technology.The sound pressure and vibration velocity on the source plane can be reconstructed from the complex sound pressure measurement data on the holographic plane by NAH.Aiming at the planar transducer array,an measurement method for self-/inter-radiation impedance characteristics of the array elements based on NAH has been proposed in this paper.The radiation impedance characteristics of the source plane can be obtained by the sound source surface information which has been reconstructed by NAH.Numerical simulation analysis for different arrays shows that,if the holographic measurement parameters are met the requirement of NAH,the reconstruction accuracy of array elements impedance characteristics would be higher.Based on the principle model for planar array impedance characteristics measurement by NAH,a software for analyzing impedance characteristics of low-frequency planar array is developed.This software can realize human-computer interaction.The test instruments could by directly controlled by this software.The measurement data could be processed,and then impedance characteristics could by displayed on the software interface immediately.The measurement experiment based on a low-frequency underwater acoustic transducer has been carried out in the anechoic pool.The software developed in this paper has been debugged.The experimental result shows that the NAH has certain feasibility in measuring the impedance characteristics of the transducer.