吸声材料对水下平台声学特性的影响

为了减小水下平台的反射系数，提高其声学隐身性能，提出了在平台表面覆盖吸声材料的方法。利用传递矩阵法，推导了水下平台复合层结构在声波斜入射条件下的反射、透射系数，计算了覆盖吸声材料前后水下平台的反射系数，并分析了材料的摆放顺序、参数变化时对平台声学特性的影响。研究结果表明，未覆盖吸声材料时，平台对声波的反射系数接近于1；覆盖吸声材料后，平台的等反射系数曲线随声波的入射角度、频率大致呈双曲线状，对高频声波的反射明显减小；平台对声波的反射具有频率选择性，增加材料的厚度可以使平台对声波的吸收频段往低频转移；当材料的损耗系数增加时，平台的反射系数降低。实验结果验证了理论计算的正确性。

Influences of Sound Absorbing Materials on Acoustic Characteristics of Underwater Platform

In order to decrease the reflection coefficient of underwater platform and promote its stealth performance, a method of covering a sound absorbing material on the platform is proposed. The transfer matrix method is used to calculate the reflection and transmission coefficients of composite structure in underwater platform in the case of oblique incidence of sound waves. The influences of the arranging sequence and parameters of sound absorbing materials on the acoustic characteristics of underwater platform are analyzed. The results show that the reflection coefficient of platform without sound absorbing material is close to 1 ; the constant reflection coefficient curve of the platform with sound absorbing material is a hyperbolic curve as the functions of incident angle and frequency, and its reflection coefficient obviously descreases at high frequency. This shows the frequency selectivity in the absorbing performance of platform, and the absorption wave band of platform transfers to lower frequencies by increasing the thickness of sound absorbing material. When the loss coefficient of material raises, the reflection coefficient of platform goes down. The experimental results coincides well with the theoretically calculated results.