Exploring rotational resonance in elastic metamaterial plates to realize doubly negative property

TL;DR

This paper demonstrates a novel elastic metamaterial that exhibits both negative effective mass density and shear modulus by leveraging rotational and resonant phenomena in a specially designed pillared structure, confirmed through simulations.

Contribution

It introduces a single-phase asymmetric double-sided pillared metamaterial with coupled resonances to achieve doubly negative properties, including chirality for enhanced rotational excitation.

Findings

Negative effective mass density achieved via bending and compression resonances.

Negative shear modulus obtained through rotational resonance.

Zero-index refraction confirmed by numerical simulations.

Abstract

We report the realization of simultaneously negative effective mass density and shear modulus in a single-phase asymmetric double-sided pillared metamaterial. The negative effective mass density is achieved by the combination of bending and compressional resonances of one pillar whereas the rotational resonance of the other pillar leads to the negative effective shear modulus. The coupling between these two pillars is investigated to describe the formation of the doubly negative property. Then, a pillared system featuring chirality is designed in order to make efficient the excitation of the rotational vibration, the occurrence of which is demonstrated by the transmission spectrum. Finally, numerical simulations of the zero-index refraction are carried out to prove the occurrence of the doubly negative property.