高频宽带嵌套式复合材料换能器*

研制了一种嵌套式高频宽带复合材料换能器，利用1-3型压电复合材料Q值较低、频带较宽的特点，采用组合式的结构拓展换能器的工作带宽。通过切割框型压电陶瓷、灌注环氧树脂得到压电复合材料框型敏感元件，再将不同厚度的框型敏感元件沿轴向嵌套从而制成多层嵌套的压电复合材料敏感元件。建立1-3型压电复合材料中压电小柱的等效电路，根据等效电路计算出压电小柱的谐振频率，并与1-3型压电复合材料的谐振频率理论计算结果进行对比。通过ANSYS软件对敏感元件结构进行仿真，并根据仿真结果确定了敏感元件的最佳设计方案。最终制作出的换能器进行水下测试，该换能器的谐振频率为310kHz，最大发送电压响应为188.5dB，-3dB带宽可达130kHz，接收灵敏度最大可达-186.8dB，-3dB带宽可达90kHz，谐振频率处-3dB的指向性开角约为2.4°。该嵌套式敏感元件可实现换能器宽带发射与接收声波的目标。

High frequency broadband nested composite transducer

A nested high-frequency broadband composite transducer is developed. Using the characteristics of low Q value and wide frequency band of 1-3 piezoelectric composite, the combined structure is adopted to expand the working bandwidth of the transducer. The piezoelectric composite frame sensitive elements are obtained by cutting frame piezoelectric ceramics and pouring epoxy resin, and then the frame sensitive elements with different thickness are nested along the axial direction to make multi-layer nested piezoelectric composite sensitive elements. The equivalent circuit of piezoelectric small column of 1-3 piezoelectric composite is established, and the resonant frequency of piezoelectric small column is calculated according to the equivalent circuit, which is compared with the theoretical calculation results of resonant frequency of 1-3 piezoelectric composite. The structure of the sensitive element is simulated by ANSYS software, and the best design scheme of the sensitive element is determined according to the simulation results. The finally fabricated transducer is tested underwater. The resonant frequency of the transducer is 310kHz, the maximum transmission voltage response is 188.5dB, - 3dB bandwidth can reach 130kHz, the maximum reception sensitivity can reach - 186.8dB, - 3dB bandwidth can reach 90kHz, and the directivity opening angle of - 3dB at the resonant frequency is about 2.4 °. The nested sensing element can realize the target of wide-band transmitting and receiving sound waves by the transducer.