含玻璃微球的黏弹性复合材料覆盖层的水下吸声性能分析

水下吸声覆盖层对潜艇的隐身具有重要的意义, 因此得到了广泛的关注. 本文对含有玻璃微球的黏弹性复合材料覆盖层的水下吸声性能进行了理论分析. 采用等效参数法计算了玻璃微球的体积含量对复合材料的力学和声学性能的影响. 应用声波在多层介质中传播的一维模型, 计算了不同玻璃微球体积含量的单层复合材料覆盖层的吸声性能.结果表明, 增加玻璃微球的体积含量可以提高覆盖层的低频吸声性能, 但是其高频吸声性能降低.采用遗传算法对玻璃微球在覆盖层厚度方向上的体积含量分布进行优化. 优化的多层结构可以在一定的频带内改善覆盖层的表面与水的声阻抗匹配, 在保证覆盖层的高频吸声系数大于某一限值(0.7)的前提下, 提高其低频吸声性能.另外, 多层优化结构覆盖层不含宏观的空腔结构, 不影响覆盖层的耐压性能.其结构简单, 对制备工艺的要求不高.因此, 本文形成的理论方法适用于水下吸声覆盖层的设计. 关键词： 水下吸声 黏弹性复合材料 玻璃微球 遗传算法

Analysis of underwater sound absorption of visco-elastic composites coating containing micro-spherical glass shell

Underwater sound absorption coating is significant to the stealth of a submarine, so it attracts a lot of attention. Underwater sound absorption of visco-elastic composites coating containing micro-spherical glass shell was investigated theoretically. The mechanical and acoustic properties of the composites in response to the volume of the micro-spherical glass shell were analyzed by the effective parameters method. Sound absorption of a single layer composites coating containing different volume of micro-spherical glass shell was calculated by the one-dimensional model, in which sound propagates in multi-layer media. The calculated results show that the sound absorption at low frequencies can be promoted by increasing the volume of micro-spherical glass shell, but the sound absorption at high frequencies is depressed. The volume distribution of the micro-spherical glass shells across the thickness of the coating was optimized by the genetic algorithm. The optimal multi-layer structure can promote the sound absorption at low frequencies, and keep the sound absorption coefficients above a limited value (0.7) at high frequencies. The optimal multi-layer composite coating can work at high pressure since it does not contain hollow macro-structure. Its structure is simple, so the technique of its fabrication should not be complicated. The theoretical method achieved in this paper can be applied in the design of underwater sound absorption coating.