Emergent dynamics of dissipative acoustic metamaterials
Mahmoud Hussein (University of Colorado Boulder), Michael Frazier (University of Colorado Boulder)
Mechanics and Dynamics of Periodic Structures
Wed 10:45 - 12:15
Salomon 101
Phononic crystals (PnCs) and acoustic metamaterials (AMs) are periodic materials that exhibit distinct frequency characteristics, such as the possibility of the formation of band gaps. Within a band gap, wave propagation is effectively prohibited. In the case of AMs, it is possible for a band gap to open up at wavelengths larger than the unit cell size. This inherent dynamical phenomenon, in PnCs and/or AMs, can be utilized in a broad range of technologies at different length scales (see [1] for a review of theory, concepts and applications). In this work, we present a rigorous formulation for the treatment of viscous damping in the analysis of elastic wave propagation in acoustic metamaterials. For simplicity, we consider a mass-spring-dashpot model and obtain exact formulae for the frequency and damping factor band structures. Our analysis sheds light on the effects of damping on the dispersive characteristics in the presence of local resonance and the realization of an emergent phenomenon which we refer to as "metadamping". 1. Deymier, P.A. (Ed.), Acoustic Metamaterials and Phononic Crystals, Springer Physics, New York, 2013.