A seismic metamaterial: The resonant metawedge.
A seismic metamaterial: The resonant metawedge.
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DOI：
10.1038/srep27717
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发表时间：
2016-06-10
影响因子：
4.6
通讯作者：
Craster RV
中科院分区：
文献类型：
--
作者：
Colombi A;Colquitt D;Roux P;Guenneau S;Craster RV
将弹性、等离子体和超材料三个不同领域的关键概念结合在一起，在地球物理尺度上设计了一种亚表面--共振亚楔体，以控制地震瑞雷波。由弹性衬底上空间梯度的垂直亚波长谐振器组成的亚楔形波，既可以将入射表面的瑞利波模式转换为整体弹性横波，也可以反射瑞利波，产生类似于电磁亚表面光学彩虹的地震彩虹效应。时间域谱元模拟证明了亚楔形波在模式转换中的宽带效应，同时开发了一个分析模型来准确地描述和预测地震彩虹效应；允许在不需要广泛的参数研究和模拟的情况下设计亚楔形波。谐振超材料的效率表明，大规模的机械超材料是可行的，将会有应用，并且在地震和地球物理的背景下考虑许多光学装置的时机已经成熟。
Critical concepts from three different fields, elasticity, plasmonics and metamaterials, are brought together to design a metasurface at the geophysical scale, the resonant metawedge, to control seismic Rayleigh waves. Made of spatially graded vertical subwavelength resonators on an elastic substrate, the metawedge can either mode convert incident surface Rayleigh waves into bulk elastic shear waves or reflect the Rayleigh waves creating a “seismic rainbow” effect analogous to the optical rainbow for electromagnetic metasurfaces. Time-domain spectral element simulations demonstrate the broadband efficacy of the metawedge in mode conversion while an analytical model is developed to accurately describe and predict the seismic rainbow effect; allowing the metawedge to be designed without the need for extensive parametric studies and simulations. The efficiency of the resonant metawedge shows that large-scale mechanical metamaterials are feasible, will have application, and that the time is ripe for considering many optical devices in the seismic and geophysical context.