Negative stiffness metamaterial elements for enhanced material damping capacity.

Abstract

Recent research has shown that the introduction of small quantities (1%–2% by volume) of constrained negative stiffness inclusions into a viscoelastic host material leads to an effective energy absorbing behavior greatly exceeding that of conventional materials [Lakes et al., Nature (London) 410, 565–567 (2001)]. The root cause of this increased absorptive capacity is the ability of the negative stiffness materials to do work on the viscoelastic host when perturbed by an incident disturbance such as a sound wave or vibrational motion [Koutsawa et al., Int. J. Mech. Mater. Des. 5, 29–44 (2007)]. A buckled beam constrained to an S‐shaped configuration has a strain energy density at a local maximum and will accordingly display negative stiffness. This negative stiffness behavior is non‐transient and broadband in nature. The buckled beam structure is therefore a compelling candidate for the construction of new metamaterials for noise reduction, anechoic coatings, and transducer backing materials. This work pr...