含螺旋结构的水下声学覆盖层吸声特性研究

Study on the Sound Absorption Characteristics of Underwater Acoustic Anechoic Coating with Spiral Structures

设计一种含圆柱空腔和金属螺旋结构的水下声学覆盖层,该覆盖层在565~5000Hz频率范围内平均吸声系数在0.85以上,具有带宽、吸声性能强的特点。通过有限元法分析该覆盖层的位移变化特点以及结构几何参数对吸声性能的影响,结果表明:金属螺旋结构的引入使基体橡胶产生反向运动(与入射波引起的基体橡胶位移方向相反),两个方向的运动在一定程度上可以相互抵消,从而消耗入射声波能量并有效提升吸声性能。叶片宽度、空腔半径、螺旋阶数的增加使得吸声峰向低频移动,但整体吸声性能会随之下降。

An underwater acoustic anechoic coating with a cylindrical cavity and a metal spiral structure was designed.The average sound absorption coefficient of this coating is above 0.85 in the frequency range of 565-5000 Hz.This coating has the characteristics of broadband and high sound absorption capacity.The effect of the displacement variation characteristics of the coating and the structural geometric parameters on the sound absorption performance are analyzed by means of the finite element method.The results show that the introduction of the metal spiral structure can cause the reverse motion of the substrate rubber(opposite to the displacement direction of the substrate rubber caused by the incident wave),and the motions in the two directions can be canceled each other to a certain extent,which consumes the incident acoustic energy and effectively improves the sound absorption performance.The increase of blade width,cavity radius and spiral order can make the absorption peak shift to lower frequency side,but the overall absorption performance will be reduced.