Broadening low-frequency bandgaps in locally resonant piezoelectric metamaterials by negative capacitance

Low frequency locally resonant metamaterials containing composite inclusions.

One main feature of metamaterials is the occurrence of a negative dynamic mass density that is produced when an inner local resonance is present. The inner resonance can be obtained in composite materials containing composite inclusions. For suitable ratios of the physical properties of the constituting materials, the composite inclusions act as spring-mass systems. The scaling of physical prop...

Piezoelectric Negative Capacitance

A thermodynamic model was constructed to analyze the negative capacitance effect in the presence of piezoelectricity. The model demonstrated that while piezoelectricity can lead to negative capacitance in principle, it is not strong enough in practice due to the unphysical amounts of charge and strain required. The inclusion of higher-order electromechanical coupling such as electrostriction ca...

Resonant Negative Refractive Index Metamaterials

Method for retrieving effective properties of locally resonant acoustic metamaterials

Acoustic metamaterials can be described by effective material properties such as mass density and modulus. We have developed a method to extract these effective properties from reflection and transmission coefficients, which can be measured experimentally. The dependency of effective properties on the positions of the boundaries of the acoustic metamaterial is discussed, and a proper procedure ...

Harnessing buckling to design tunable locally resonant acoustic metamaterials.

We report a new class of tunable and switchable acoustic metamaterials comprising resonating units dispersed into an elastic matrix. Each resonator consists of a metallic core connected to the elastomeric matrix through elastic beams, whose buckling is intentionally exploited as a novel and effective approach to control the propagation of elastic waves. We first use numerical analysis to show t...