水下均匀材料复合层吸声特性研究

本文对水下阻尼板和其它介质层复合的多层吸声和结构吸声，反声性能进行了研究，利用各层界面压力，振速的四端网络矩阵及层间边界条件导出吸声结构表面阻抗和反射系统数随频率的变化关系，数值计算分析了不同边界条件，多种层以及改变各层参数情况，反声，吸声系数的变化，发现多层结构中厚的水层引起强烈的共振反射峰，并提出了抑制共射的方法。

Investigation of the sound absorption of homogeneous composite multiple-layer structures in water

In this paper, we investigate the sound absorption of underwater composite structures, which are composed of an absorbent layer and non-absorbent layers. Using the transfer matrix of sound pressure and particle velocity of each layer and the continuity condition at the interface between two layers, input impedance and reflection response of the composite structures are deduced. By numerical calculation, we analyse the variation of the reflection response of the structures when the boundary conditions of the structures and the parameters of each layer are changed. It is found that there are many resonance reflection peaks which are caused by the thick water layer in the sturcture and we present a method to reduce the peaks.