Bucciarelli F, Malfense Fierro G P, Rapisarda M, Meo M
Department of Mechanical Engineering, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
Sci Rep. 2022 Aug 26;12(1):14611. doi: 10.1038/s41598-022-14415-3.
Low frequency broadband sound absorption for thin structures is still a great challenge. A new concept of a stackable hybrid resonator metamaterial is proposed which exhibits super broadband low-frequency sound absorption. The proposed metamaterial is based on micrometric scale thickness Graphene Oxide (GO) embedded in a stacked structure or used as external skin in a designed honeycomb (HC) structure. The stackable nature of the proposed structure allows the GO-HC cores to be embedded within micro-perforated panels (MPP) providing enhanced stiffness/strength to the structure and high absorption characteristics. We demonstrate how the exploitation of the GO elastic and mass properties result in multiple hybrid structural-acoustic resonances. These resonances are tailored to occur in a frequency range of interest by the theoretical calculation of the sound absorption coefficient. The theoretical model combines the mutual interaction between the structural dynamic of the GO foil and acoustic higher modes of the HC core cell as well as stacked MPP-HC/GO-HC cores. The result is a multi-degree of freedom hybrid resonator which provides subwavelength scale broadband sound absorption in low frequency range between 300 and 2500 Hz.
薄结构的低频宽带吸声仍然是一个巨大的挑战。本文提出了一种可堆叠的混合谐振器超材料的新概念，它具有超宽带低频吸声特性。所提出的超材料基于微米级厚度的氧化石墨烯（GO），其嵌入堆叠结构中或用作设计的蜂窝（HC）结构的外皮。所提出结构的可堆叠特性使得GO-HC芯能够嵌入微穿孔板（MPP）内，从而为结构提供增强的刚度/强度以及高吸声特性。我们展示了如何利用GO的弹性和质量特性产生多个混合结构 - 声学共振。通过吸声系数的理论计算，这些共振被调整到感兴趣的频率范围内发生。理论模型结合了GO箔的结构动力学与HC芯单元以及堆叠的MPP-HC/GO-HC芯的声学高阶模式之间的相互作用。结果是一个多自由度混合谐振器，它在300至2500 Hz的低频范围内提供亚波长尺度的宽带吸声。
