水中夹层复合材料表面声反射的研究

The study of sound reflection at the surface of sandwich GFRP in water

为了降低水下航行器和物体表面的声反射和声辐射强度,可以采用玻璃钢夹层结构代替单层玻璃钢结构.利用传递矩阵法得到了多层介质声波反射透射的计算公式,通过对一个实验样本的计算和实验测试结果比较,表明此种计算方法可行.在此基础上,仿真模拟计算了层厚度、夹芯的密度、声速、厚度等参数改变时,玻璃钢夹层结构的声压反射系数,分析比较了玻璃钢夹层替代单层玻璃钢表面的声反射特性.研究表明:在频率小于15 kHz范围内,玻璃钢夹层可以使声波的反射控制在很小的范围,配合吸声涂层的使用,可以在更大的频率范围内达到很好的声隐身效果.

To reduce the acoustic target strength of submarines and other underwater objects, a single layer of glass fibrous reinforced composites （GFRP） was replaced by a sandwich of the material. The expressions of sound reflection and transmission coefficients in multi-medium system were obtained by transfer matrix. The sound reflection of a specimen of sandwich glass fibrous reinforced composites material was calculated. The results were compared with that of measurement by pulse wave tube, which shows that the method is able to be applied to calculate sound transmission in multi-layer underwater. Then, by numerical calculation, the variation of the coefficients of sound reflection with the parameters of sandwich layers was analyzed. The characteristics of sound reflection on the surface of a sandwich GFRP was compared with that on the surface of a single GFRP. The study shows that reflection of a sandwich GFRP is small in the range of frequency that is lower than 15 kHz and in wider range with a sound absorption coat.