Liu Botao, Huang Sibo, Zheng Bo, Chen Xuefeng, Zhao Jia, Qi Xinrui, Li Yong, Liu Shengchun
Acoustic Science and Technology Laboratory, Harbin Engineering University, Harbin 150001, China.
Institute of Acoustics, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China.
J Acoust Soc Am. 2023 Jan;153(1):415. doi: 10.1121/10.0016864.
The underwater sound absorption technique in low-frequency and broadband has far-reaching prospects since it is essential for noise reduction of deep-sea operation requirements and evading advanced underwater target detection. Here, we propose an underwater sound-absorbing composite lattice with low-frequency and ultra-broadband characteristics. The composite lattice is constructed by regular spatially stacking cells with different sizes of metallic core spheres. All the core spheres are coated with silicon rubbers, and cells are embedded in the rubber matrix. In the composite lattice stereostructure, the lattice cells convert incident longitudinal waves into transverse waves through multiple local resonance coupling and multiple scattering. The energy is localized and dissipated in the composite lattice. We analyze the relationship among the corresponding absorption spectrums, the displacement clouds, and the resonance modes of lattice cells. Then, we construct a composite lattice and realize low-frequency broadband absorption from 693 to 1106 Hz with absorptance above 0.8. Further, our investigation demonstrates that the absorption bandwidth can be extended to ultra-broadband from 1077 to 10 000 Hz, where the thickness of the composite lattice is λ/17.05. The proposed composite lattice provides a practical approach to designing ultrathin low-frequency and ultra-broadband acoustic absorption coating for underwater noise suppression.
低频宽带水下吸声技术对于深海作业要求的降噪以及躲避先进水下目标探测至关重要，因此具有深远的应用前景。在此，我们提出一种具有低频和超宽带特性的水下吸声复合晶格。该复合晶格由具有不同尺寸金属核心球体的单元规则地空间堆叠而成。所有核心球体均涂覆有硅橡胶，单元则嵌入橡胶基体中。在复合晶格立体结构中，晶格单元通过多次局部共振耦合和多次散射将入射纵波转换为横波。能量在复合晶格中局部化并耗散。我们分析了相应的吸收频谱、位移云图和晶格单元共振模式之间的关系。然后，我们构建了一个复合晶格，并实现了693至1106赫兹的低频宽带吸收，吸光度高于0.8。此外，我们的研究表明，吸收带宽可以扩展到1077至10000赫兹的超宽带，此时复合晶格的厚度为λ/17.05。所提出的复合晶格为设计用于水下噪声抑制的超薄低频和超宽带吸声涂层提供了一种实用方法。
