In this paper we present experimental and theoretical results on an acoustic metamaterial bar that exhibits negative effective mass and negative effective stiffness. A one-dimensional acoustic metamaterial bar with an group of non-linear spring-mass cells in was fabricated. The frequency characteristics of the acoustic metamaterial have the same form as that of the permittivity in metals due to the plasma oscillation. We also provide a theory to explain the simulation results. And numerical simulations reveal that the actual working mechanism of the proposed metamaterial bar is based on the concept of conventional mechanical vibration absorbers. It uses the incoming elastic wave in the bar to resonate the integrated spring-mass-damper absorbers to vibrate in their optical mode at frequencies close to but above their local resonance frequencies to create shear forces and bending moments to straighten the bar and stop the wave propagation. Moreover, we design a finite periodic system composed of such basic units to confirm that the modeling and analysis techniques are available.

Date Published: 1 April 2016
PDF: 10 pages
Proc. SPIE 9806, Smart Materials and Nondestructive Evaluation for Energy Systems 2016, 980615 (1 April 2016); doi: 10.1117/12.2219573

Published in SPIE Proceedings Vol. 9806:
Smart Materials and Nondestructive Evaluation for Energy Systems 2016
Norbert G. Meyendorf; Theodoros E. Matikas; Kara J. Peters, Editor(s)