单矢量水听器水声材料声反射系数自由场测量

Measurement of the acoustic reflection coefficient of underwater acoustic materials based on a single vector hydrophone

针对测量中试样边缘衍射效应与多途干扰的问题,本文提出了一种斜入射条件下水声材料声反射系数宽带测量方法。结合脉冲声发射技术与后置逆滤波技术,在时域上剔除干扰声信号;随后将单矢量水听器看作三元接收阵,充分利用单矢量水听器接收信号模型特点,通过求解超定方程组分离直达声与反射声,解决了信号混叠的问题。数值仿真与实验研究结果表明:本文所述测试方法可有效实现斜入射条件下的水声材料声反射系数的自由场大样测试,但受限于发和换能器的低频发射能力,实验结果在高频段与理论值吻合较好。

A novel method is presented for measuring the acoustic reflection coefficient of underwater acoustic materials in the free field using a single vector hydrophone,to solve the problems of edge diffraction effect and signals aliasing.The postprocessing filter and acoustic impulse transmitting technologies are introduced into the measurement,which is beneficial for eliminating acoustic interference signals.Next,the single vector hydrophone is regarded as a ternary receiving array,which fully uses the characteristics of the single vector hydrophone model receiving signal and separates the direct and reflected sounds by solving the overdetermined equations,thereby solving the problem of signal aliasing.The numerical simulation and experimental results show that the testing method described in this paper can effectively measure the acoustic reflection coefficient of underwater acoustic materials under oblique incidence in the free field,but this method is limited by the low-frequency emission ability of the transmitter and transducer.The experimental results are in good agreement with the theoretical values in the high-frequency band.