Performance and influencing factors of acoustic grating based on signal enhancement

In the acoustic signal receiving section of underwater vehicle, an effective measure to improve surface acoustic impedance and reduce signal attenuation is to cover acoustic barrier plate of hydrophone array with high impedance material (signal conditioning plate). Compared with traditional full coverage mode, an acoustic grating (periodic installation of regulator plate array) can greatly improve the received signal gain and reduce the weight of the receiving segment. In order to deeply understand the signal enhancement mechanism and optimize the design of acoustic grating, the factors that influence the signal enhancement performance of acoustic grating from the aspects of width, thickness, incident angle and structure width ratio is studied. Simulation results show that the oblique incidence will change the symmetrical distribution of signal ratio (SR), but will not significantly change the acoustic performance of the structure. Wider and thicker regulating plate lead to stronger non-mirror scattering and better signal enhancement performance of structure. In practical application, geometric parameters of acoustic grating should be reasonably designed to meet multiple constraints of real environment to achieve optimal overall performance. In addition, the moderate width ratio can obtain a good overall acoustic performance. 对于安装在水下航行器声信号接收段的水听器阵列, 在其声障板上覆盖高声阻抗材料(称为信号调节板)是一种能有效提高表面声阻抗并减少信号衰减的措施。相比传统的完全覆盖方式, 声栅结构(即周期性地敷设调节板阵列)可以极大地提高接收信号增益, 减小接收段的质量。为了深入理解声栅结构信号增强机理, 优化声栅结构设计, 研究了调节板宽度、调节板厚度、入射角以及结构宽度比等因素对声栅结构信号增强性能的影响。仿真结果表明: 斜入射会改变信号比(SR)的对称分布, 但不会大幅改变结构的声学性能; 调节板越宽、越厚, 引起的非镜面散射会更强, 声栅结构的信号增强性能就越好。在实际应用中, 应合理设计声栅结构几何参数以满足现实环境的多重约束以达到总体性能最优, 此外适中的宽度比能获得良好的总体声学性能。