Lee Hyung Jin, Lee Je-Ryung, Moon Seung Hwan, Je Tae-Jin, Jeon Eun-Chae, Kim Kiyean, Kim Yoon Young
Institute of Advanced Machines and Design, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, South Korea.
Korea Institute of Machinery and Materials (KIMM), 156 Gajeongbuk-ro, Yuseong-gu, Daejeon, 34103, South Korea.
Sci Rep. 2017 Nov 13;7(1):15378. doi: 10.1038/s41598-017-15746-2.
The polarization anomaly refers to the polarization transition from longitudinal to shear modes along an equi-frequency contour of the same branch, which occurs only in some anisotropic elastic media, but the lack of natural materials exhibiting desired anisotropy makes its utilization impossible for potential novel applications. In this paper, we present a unique, non-resonant type elastic metamaterial made of off-centered, double-slit unit cells. We show that its wave polarization characteristics that determine the desired anomalous polarization for a certain application are tailorable. As an application, a mode converting wedge that transforms pure longitudinal into pure shear modes is designed by the proposed metamaterial. The physics involved in the mode conversion is investigated by simulations and experiments.
极化异常是指在同一分支的等频轮廓线上从纵向模式到剪切模式的极化转变，这种现象仅在某些各向异性弹性介质中出现，但缺乏展现所需各向异性的天然材料使得其无法用于潜在的新型应用。在本文中，我们展示了一种由偏心双缝单元构成的独特的非共振型弹性超材料。我们表明，其决定特定应用所需异常极化的波极化特性是可定制的。作为一个应用实例，我们利用所提出的超材料设计了一种将纯纵向模式转换为纯剪切模式的模式转换楔。通过模拟和实验研究了模式转换所涉及的物理过程。
