Research On High Frequency Broadband Directivity Controllable Cylindrical Array Transducer

In this paper,a high frequency and wide band directivity controllable cylindrical array sensor and its transducer are developed.The structure of the cylindrical array sensor is composed of piezoelectric ceramic column,epoxy resin and silicone rubber.The equivalent circuit diagram and electromechanical equivalent diagram are obtained by physical analysis of the approximate model of the single ring of the sensitive element with theoretical physical knowledge.Using finite element analysis method,the equivalent physical model of the transducer is modeled and simulated,and the conductivity curve of the transducer in high frequency state is obtained.Two existing methods to expand the bandwidth of the transducer are adopted comprehensively.One is to add flexible polymers(such as epoxy resin,polyurethane,etc.)to reduce the mechanical quality factor Qm value of the material and expand the bandwidth of the material.Secondly,based on the theory of multi-mode coupling vibration,the longitudinal stacking process of rings with different thicknesses is adopted to meet the requirements of broadband operation of the transducer.The fabrication process of the sensor is given.and the geometry of the piezoelectric composite material is transformed from a plane to a curved circle,which enlarges the beam opening Angle of the transducer.The piezoelectric composite single ring with the same outer diameter,different inner diameter and the same height was fabricated.The single ring sensor of the piezoelectric composite material was divided into several piezoelectric array elements by a special electrode segmentation process,and all the array elements were separately led out of the electrode leads to make the single ring array sensing element.Different single ring array sensing elements were stacked longitudinally and cylindrical array stacked sensing elements with horizontal ring array and vertical vertical array were fabricated.According to the size of the sensitive element,the structure of the underwater acoustic transducer is designed reasonably,the manufacturing process of the underwater acoustic transducer is studied,and the structural accessories and pouring mold for encapsulating the sensitive element are made.The mixed liquid of waterproof and sound permeable layer is configured,and the sensitive element is poured,solidified and demoulded by the designed and manufactured glue injection mold.Finally,the cylindrical array underwater acoustic transducer with high frequency and wide band directivity is developed.The performance test of the underwater acoustic transducer shows that the frequency range of-3 dB bandwidth of the transducer is 240 kHz?326 kHz.the bandwidth is up to 86 kHz,the maximum transmission voltage response is 154 dB,the receiver sensitivity of the transducer is up to-206 dB.and the directivity control range is from 0° to 360°.It can be seen from the above results that the design goal of high frequency,wide band and controllable directivity of the transducer has been achieved in this paper.