自由端盖四梁凹形宽带弯张换能器设计

Design of broadband square barrel-stave transducer with decoupling end caps

针对凹形弯张换能器改善低频宽带工作特性的技术需求,提出了一种自由端盖四梁凹形弯张换能器新结构。结构中将纵向振子的端部设计成弹性辅助梁,与主弯曲梁连接构成复合弯曲梁。同时为了克服弹性辅助梁对振动辐射带来的不利影响,引入了由纵向振子驱动的方形自由端盖并以此构成新的辐射端面。利用有限元软件分析了这种新结构弯张换能器的多模振动特性,模态分析表明换能器的前五阶模态是可利用的主要工作模态,频率间隔可以通过敏感结构参数进行调控。通过优化给出了一种设计方案,换能器整体几何尺寸为140 mm×140 mm×396 mm,仿真分析了换能器在水中的导纳特性和发射电压响应曲线,结果表明:换能器最大发射电压响应大于145 dB,发射电压响应起伏小于6 dB的工作频带为1.5~4.3 kHz,发射电压响应起伏小于10 dB的工作频带为1.5~8 kHz,具有低频宽带大功率工作特性。

In order to improve the low-frequency broadband performance of the barrel-stave transducer,a new structure of four-beam square barrel-stave transducer with decoupling end caps is proposed.The structure at the end of the PZT longitudinal vibrator is an elastic auxiliary beam,which is connected with the concave flexural beam to form a composite flexural beam.In order to reduce the adverse effects of the auxiliary beam on the acoustic radiation,square decoupling end caps driven by longitudinal driver are designed as new radiating surfaces.The modal analysis is made at first,which shows that frequency spacing between the available first five class modes could be adjusted by several characteristic structural parameters effectively.An optimal design of the transducer is presented with the overall geometric size 140 mm×140 mm×396 mm.Then the admittance and transmitting voltage response are simulated and analyzed.It is shown that the maximum transmitting voltage response is greater than 145 dB.The−6 dB frequency range is from 1.5 kHz to 4.3 kHz,and−10 dB frequency range from 1.5 kHz to 8 kHz.The low-frequency,broadband and high power performances of the transducer are confirmed by these results.