水下夹芯复合空腔结构声学特性试验研究

摘要

引入空腔改善夹芯复合结构低频段吸声性能。建立了三种典型水下声隐身结构声学系统模型，在数值分析吸声性能影响因素基础上，运用脉冲声管试验方法，分析了空气背衬“硬”边界条件和水背衬“软”边界条件下，有无空腔试样、不同空腔间距、空腔形状和深度对谐振吸声峰值及峰值频率等的影响。试验结果表明，空腔显著改善了夹芯复合结构低频段吸声性能；空气背衬下，空腔间距越小，首阶谐振吸声峰值越大，峰值频率越低，水背衬条件下则相反；空腔体积越大，首阶谐振吸声峰值越小，峰值频率越低。%Introducing cava can improve the sound-absorption ability of a sandwich composite structure within a low-frequency range.The acoustic models for 3 kinds of typical underwater acoustic-stealth structures were established. The affect factors of their sound-absorption ability were analyzed numerically.Then,using the test method of pulse sound tube,the effects of samples with cava or without cava,different distances between cava,shape and depth of cava on the peak value of sound-absorption resonance and its frequency of the structures were analyzed under hard boundary condition and air background as well as soft boundary condition and water background.The results showed that the cava obviously improve the sound-absorption ability of sandwich composite structures within a low-frequency range;under air background,the smaller the distance between cava,the larger the peak value of the 1 st order sound-absorption resonance and the lower the corresponding frequency;under water background,the situation is the opposite;the bigger the volume of cava,the smaller the peak value of the 1 st order sound-absorption resonance and the lower the corresponding frequency.