Constrained negative stiffness metamaterials.

Abstract

Acoustics‐oriented metamaterial research has focused primarily on the use of subwavelength resonant structures to elicit unconventional macroscale properties such as negative mass, anisotropic density, and negative stiffness. Unfortunately, reliance on resonant behavior limits the usefulness of these types of metamaterials to a narrow band of frequencies. One intriguing manifestation of negative stiffness, however, does not require resonant behavior and is therefore useful over a broader range of frequencies. This type of negative stiffness relies on constrained bistable structures and is known as constrained negative stiffness (CNS). The present work investigates the use of CNS mechanisms for vibration isolation and acoustic wave attenuation. A linearized analytical model of a constrained buckled beam structure is presented to predict system behavior and stability, and investigate the fundamental physical behavior leading to increased energy absorption. Experimental studies are then shown confirming model predictions. Finally, a 1‐D candidate acoustical metamaterial containing CNS inclusions is modeled and analyzed.