A two-dimensional phononic crystal (PC) can exhibit longitudinal-mode negative energy refraction on its lowest (acoustical) frequency pass band. The effective elastodynamic properties of a typical PC are calculated and it is observed that the components of the effective density tensor can achieve negative values at certain low frequencies on the acoustical branches for the longitudinal-mode pass-band, and that negative refraction may be accompanied by either positive or negative effective density. Furthermore, such a PC has a high anisotropy ratio at certain low frequencies, offering potential for application to acoustic cloaking where effective material anisotropy is essential.
- Aerospace Division
Two-Dimensional Phononic Crystals With Acoustic-Band Negative Refraction
Sadeghi, H, & Nemat-Nasser, S. "Two-Dimensional Phononic Crystals With Acoustic-Band Negative Refraction." Proceedings of the ASME 2016 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. Volume 2: Modeling, Simulation and Control; Bio-Inspired Smart Materials and Systems; Energy Harvesting. Stowe, Vermont, USA. September 28–30, 2016. V002T03A002. ASME. https://doi.org/10.1115/SMASIS2016-9025
Download citation file: