外层壳及其阻尼对水中双层球壳声散射的影响

研究了浸没于水中的双层球壳振动问题，利用已得到的散射率函数，计算并分析了外层壳的厚度、材料常数、粘性阻尼等对双层球壳散射特征的影响，计算结果显示：当外层材料系数比内层小许多时，外层壳对散射率一频率曲线上的单极峰和第二个双极峰影响不大，但对第一个双极峰影响较大，且第一个双极峰对材料的阻尼系数非常敏感，分析了产生这些现象的具体原因。

Effects of an outer layer and its damping on acoustic scattering characteristics of a double-layered spherical shell immersed in water

The oscillation of an air-filled double-layered spherical shell immersed in water was examined. By the use of the obtained relationship between reflectively and frequency, the effects of thickness, material coefficients and viscoelastic damping of outer shell on the scattering characteristics of the structure were calculated and analyzed. When the outer layer was much softer than the inner one, the obtained results showed that the outer layer had less influence on the monopole and the second dipole but larger influence on the first dipole of one-order. The first dipole was sensitive to the damping coefficient of the outer layer. The real reasons of these phenomena were investigated.