双层弹性支撑板的水下宽带隔声

Underwater broadband sound insulation of double plates connected elastically

为实现水下宽带隔声,提出了一种由弹性元件支撑两块刚性端板构成的双层弹性支撑板结构。采用弹簧振子振动分析法和声传播理论,建立了平面波入射的水下隔声理论模型,分析了结构参数对隔声量的影响规律,结果表明足够小的弹性元件单位面积弹性系数或足够大的端板单位面积质量都可以连续一致地提高隔声量.仿真分析了双层弹性支撑板的振动位移和声输入阻抗,比较了双层弹性支撑板与连续介质层的隔声特性,结果表明,降低弹性元件质量,有助于在低频段消除半波全透射现象.在同厚度、同质量、同静态压缩率条件下,双层弹性支撑板能更好的降低两侧流体的振动及声耦合,隔声频带更宽,带内一致性更好,隔声量更大.

A double-plate structure with elastic connection,in which two parallel rigid plates are supported by an elastic connecting element,is developed to achieve underwater broadband sound insulation.Using the method of vibration analysis of spring vibrator and the theory of sound propagation,the sound insulation theoretical model under the plane wave incidence is developed,and the influences of structure parameters on the sound insulation is analyzed.The sound transmission loss will increase consistently by reducing the elastic coefficient per unit area sufficiently or increasing the mass per unit area of the end plate sufficiently.Through the finite element simulation,the vibration displacement and acoustic input impedance of the double-plate structure are analyzed,and the sound insulation characteristics of the double-plate structure and the continuous media layer,such as the uniform elastic layer and the elastic layer with cavities,are compared.The results show that reducing the mass of elastic element is helpful to eliminate the half-wavelength full transmission phenomenon at low frequency.Compared with the continuous media layer with the same thickness,quality and static compression ratio,the double-plate structure with elastic connection can reduce the vibration and sound coupling of the bilateral fluid more effectively,and have better sound insulation performance with wider bandwidth,better in-band consistency and larger sound transmission loss.