1-3型二维柱形凹面线聚焦换能器声场特性

The acoustic field characteristics of 1-3 piezocomposite two-dimensional cylindrical concave line-focusing transducer

设计并研制了柱面结构的1-3型复合材料凹面线聚焦换能器,在提高换能器带宽的同时,可以实现声场的线聚焦。将换能器内部PZT柱作为独立声源,应用瑞利积分和叠加原理,推导出了柱形凹面换能器总声场的理论表达式。通过仿真计算分析了换能器在聚焦线上的声场特点以及相关参数对聚焦性能的影响。对换能器参数做出合理设计,使换能器在实现线聚焦的同时,声场在聚焦线上的起伏较小,从而设计并制作出聚焦性能良好的线聚焦凹面换能器探头。实验测试结果表明采用本文方法计算得到的换能器声场与实测的声场分布基本符合,柱形凹面换能器在其几何焦点附近范围内均可实现聚焦,并在侧向上形成清晰的聚焦线,其聚焦线长度为换能器的侧向结构长度,在聚焦线上声场分布起伏较小。

A line-focusing transducer based on a cylindrical concave structure of 1-3 piezoelectric composite material is designed and developed,which could achieve both a nice line focus and a high bandwidth.Taking the PZT column inside the transducer as an independent sound source,the theoretical expression of the total sound field of the cylindrical concave transducer is derived by applying the Rayleigh integration and superposition principle.The model proposed in this paper is used to calculate the sound field directivity of the transducer in the lateral and side directions.The sound field characteristics of the transducer on the focusing line and the focusing performance affected by transducer parameters are analyzed.Reasonable design of the transducer parameters is proposed to make the focusing line as wide as possible,while keeping a small fluctuation of the focused sound field.It is shown by the experimental test results that the calculated sound field is basically in line with the measured value.It is also shown that the concave transducer forms a clear focusing line in the lateral direction in the vicinity of its geometric focus and the length of the focusing line equals to the lateral length of the transducer.The distribution of sound field fluctuates slightly on the focusing line.