The Study Of Longutudinal Transducer And Plane Array

As sonar equipment is developing towards the directions low-frequency,high power,signal processing and high search,the demands of transducer are increasing.Constantly single transducer has been unable to meet the complex demands.Instead of single transducer,transducer array has better performance achieving the indicator of modern sonar.The longitudinal transducer is always used in transducer arrays because longitudinal transducer has advantages of simple structure,small size and easy to array.An plane array will be made up with eight longitudinal transducers in this paper.Firstly,the longitudinal transducer will be analyzed with equivalent circuit method.The electroacoustical characteristic of longitudinal transducer is analyzed by the equivalent-circuit diagram.Then the finite element software ANSYS is used to analyze the transducer.With the finite element model,admittance curves and transmitting voltage response curves could be got,and the regularity of how the main parameters affect the performance of the transducer could be got.Finally,the structure size parameters of the transducer is optimized,getting a virtual prototype,which can be used within frequency range 20-40 kHz with the peak transmitting voltage response 146.5dB,fluctuation less than 3dB.This is the array element of the eight element plane array.Secondly,by the theory of mutual radiation,the regularity of the radiation impedance of the array and the array element when the distance of element and the frequency is changed is analyzed;by the theory of directivity,the regularity of the beam pattern of the array when the distance of element and the frequency is changed is analyzed and the beam pattern is corrected based on the theory of mutual radiation;considering the radiant efficiency and-3 dB beamwidth,the distance of the element is determined.Then using the finite element software ANSYS to verify the result of theory calculation.Finally,a virtual prototype which can be used within frequency range 20-40 kHz with the peak transmitting voltage response 164.2dB,fluctuation less than 4.5dB,and the biggest-3 dB beamwidth of 4 elements and 2 elements successively are 15 ? and 28 ? could be got.At last,based on the result of simulating calculation,twelve longitudinal transducers which can be used within frequency range 20-40 kHz with the peak transmitting voltage response 151 dB,fluctuation less than 6dB are made.The eight-element plane array is made up with 8 transducers which are picked from twelve transducers.The performance of the prototype is within frequency range 20-40 kHz with the peak transmitting voltage response 166 dB,fluctuation less than 6.4dB,and the biggest-3 dB beamwidth of 4 elements and 2 elements successively are 14 ? and 32 ?.