【摘要】 本文提出一种内嵌粗糙弯曲颈部的赫姆霍兹可调性水下吸声超表面，该结构是在金属六边形赫姆霍兹谐振器中引入橡胶涂层和粗糙弯曲金属颈部，可以实现水下低频宽带高效吸声。与传统的谐振器相比，该超表面单元的吸声峰值对应的频率可低至151 Hz，并且有限元和理论模型计算的吸声系数基本吻合。固定超表面单元的外部几何参数不变，调整内部几何参数（橡胶涂层厚度和内嵌颈部相对粗糙度等），以实现完美声学超表面的频率可调性。为实现工程应用中的宽带吸声性能，本文将4个超表面单元共面平行排列形成复合声学超表面。厚度为50 mm的复合吸声结构在75～201 Hz的频率范围内，实现了带宽为126 Hz的低频宽带高效吸声（吸声系数>0.8）。本文研究对水声超表面的设计和水下低频噪声控制具有重要意义。更多还原

【Abstract】 In this paper, a flexible underwater sound absorption metasurface with embedded rough curved neck is proposed. This structure is based on the introduction of rubber coating and rough curved metal neck in metal hexagonal Helmholtz resonator, which can realize high efficiency underwater low frequency broadband sound absorption. Compared with the traditional resonator, the frequency corresponding to the peak absorption of the metasurface unit can be as low as 151 Hz,and the absorption coefficient calculated by the finite element is basically consistent with the theoretical model. The external geometric parameters of the fixed metasurface element are unchanged, and the internal geometric parameters(thickness of the rubber coating and relative roughness of the embedded neck, etc.) are adjusted to achieve the frequency tunability of the perfect acoustic metasurface. In order to achieve wide-band sound absorption performance in engineering applications, four metasurface elements are arranged in parallel to form a compound acoustic metasurface. The composite sound absorption structure with a thickness of 50 mm achieves a low frequency broadband and efficient sound absorption with a bandwidth of126 Hz(sound absorption coefficient >0.8) in the frequency range of 75～201 Hz. The research in this paper is of great significance to the design of underwater acoustic metasurface and the control of underwater low frequency noise.更多还原