Locally resonant metamaterial curved double wall to improve sound insulation at the ring frequency and mass-spring-mass resonance
Locally resonant metamaterial curved double wall to improve sound insulation at the ring frequency and mass-spring-mass resonance
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DOI：
10.1016/j.ymssp.2020.107179
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发表时间：
2021-02
影响因子：
8.4
通讯作者：
Zibo Liu;Romain Rumpler;Leping Feng
中科院分区：
文献类型：
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作者：
Zibo Liu;Romain Rumpler;Leping Feng
提出并研究了一种局部谐振的超材料弯曲双壁结构。其目的是通过引入针对与弯曲双壁的特征频率相关联的窄频带区域的超材料设计来改善隔音，从而能够在更宽的频率范围内全面改善隔音性能。这种超材料是通过在弯曲的双壁上引入周期性分布的谐振器来实现的。本文首先用“表观阻抗”的概念研究了这种弯曲双层壁的透声损失特性，表观阻抗是用组成板和空气腔的阻抗来表示整个结构的特性。表观阻抗法是针对有限元模型进行验证。它示出，而不是一个单一的弯曲面板的环频率周围的声音传输损失的下降，弯曲的双壁可能会表现出广泛的“谷”与低的声音传输损失，其带宽是由结构的两个特征频率之间的间距（与环频率和质量弹簧质量共振的弯曲双壁）。然后，通过将两个特征频率调整为彼此接近来专门设计弯曲的双壁，以便使与低传输损耗相关联的区域变窄。随后，这使得能够通过有效地插入调谐的局部谐振器来改善该区域中的传输损耗。讨论了双层曲面板的设计原则，并介绍了由相同曲面板和不同曲面板组成的双层曲面板的应用。
A locally resonant metamaterial curved double wall is proposed and studied. The aim is to improve the sound insulation by introducing a metamaterial design targeting a narrow frequency band region associated with characteristic frequencies of curved double walls, thus enabling an overall improvement of sound insulation properties in a broader frequency range. This metamaterial is realized by introducing periodically distributed resonators to a curved double wall. The sound transmission loss properties of such curved double walls are first investigated by using the concept of ‘apparent impedance’, which expresses the properties of the whole structure in terms of the impedances of the constituting panels and air cavity. The apparent impedance approach is validated against Finite Element models. It is shown that, instead of a dip in the sound transmission loss around the ring frequency of a single curved panel, the curved double wall may exhibit a broad ‘valley’ with low sound transmission loss, whose bandwidth is determined by the spacing between the two characteristic frequencies of the structure (associated with the ring frequency and mass-spring-mass resonance of the curved double wall). The curved double wall is then specifically designed by adjusting the two characteristic frequencies to be close to each other in order to narrow the region associated with a low transmission loss. This enables, subsequently, to improve the transmission loss in this region by effectively inserting tuned local resonators. The design principles are discussed, and applications of double walls consisting either of the same curved panels or different curved panels are both included.