We report on a new mechanism involving the torsional resonance of stubs to achieve the negative effective shear modulus of an elastic metamaterial plate. Combined with a mechanism to create a negative mass density, we develop a general method to set up and enlarge a shear-horizontal-polarized double-negative branch in the elastic metamaterial plate with stubs on both sides. We explore the capabilities of this structure for polarization filtering, mode conversion and abnormal refraction. It is shown that, this metamaterial plate behaves divergently against the polarization of incident waves propagating along ΓX direction in a square lattice crystal: it behaves as a double-negative system for zero-order shear horizontal (SH0) wave but as a single-negative one for zero-order antisymmetric (A0) or symmetric (S0) Lamb waves. Mode conversion is achieved when the propagation deviates from ΓX direction. Moreover, we observe abnormal refracted patterns with both positive and negative refraction occurring at the interface between a prism-shaped supercell and the surrounding plate. Furthermore, we propose a chiral pillar to efficiently couple the torsional resonance with an incident A0 Lamb wave.

中文翻译：

---

具有扭转共振的弹性短截线超材料板

我们报告了一种涉及短柱扭转共振的新机制，以实现弹性超材料板的负有效剪切模量。结合产生负质量密度的机制，我们开发了一种通用方法，在两侧带有短截线的弹性超材料板中建立和扩大剪切-水平-极化双负分支。我们探索了这种结构在偏振滤波、模式转换和异常折射方面的能力。结果表明，该超材料板对在方形晶格晶体中沿 ΓX 方向传播的入射波的极化具有发散性：它对于零级剪切水平 (SH0) 波表现为双负系统，但表现为单负系统一种用于零阶反对称 (A0) 或对称 (S0) 兰姆波。当传播偏离ΓX 方向时实现模式转换。此外，我们观察到异常折射图案，在棱柱形超级单体和周围板之间的界面处发生正折射和负折射。此外，我们提出了一种手性柱来有效地将扭转共振与入射的 A0 Lamb 波耦合。