title: Anomalous wave propagation in a one-dimensional acoustic metamaterial having simultaneously negative mass density and Young's modulus.
abstract: A mechanical model representing an acoustic metamaterial that exhibits simultaneously negative mass density and negative Young's modulus was proposed. Wave propagation was studied in the frequency range of double negativity. In view of positive energy flow, it was found that the phase velocity in this range is negative. This phenomenon was also observed using transient wave propagation finite-element analyses of a transient sinusoidal wave and a transient wave packet. In contrast to wave propagation in the region of positive mass and modulus, the peculiar backward wave motion in the region of double negativity was clearly displayed.
authors.affiliation: Department of Engineering Science and Ocean Engineering, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: H H
authors.initials: HH
authors.lastname: Huang
authors.forename: C T
authors.initials: CT
authors.lastname: Sun
mesh_terms: D000162:Acoustics / Q000295:instrumentation*; D003198:Computer Simulation; D055119:Elastic Modulus; D004867:Equipment Design; D020342:Finite Element Analysis; D008420:Manufactured Materials; D008962:Models, Theoretical; D009038:Motion; D009716:Numerical Analysis, Computer-Assisted; D013016:Sound; D013997:Time Factors