Highly anisotropic elements for acoustic pentamode applications

Phys Rev Lett. 2013 Jul 12;111(2):024302. doi: 10.1103/PhysRevLett.111.024302. Epub 2013 Jul 10.

Abstract

Pentamode metamaterials are a class of acoustic metafluids that are characterized by a divergence free modified stress tensor. Such materials have an unconventional anisotropic stiffness and isotropic mass density, which allow themselves to mimic other fluid domains. Here we present a pentamode design formed by an oblique honeycomb lattice and producing customizable anisotropic properties. It is shown that anisotropy in the stiffness can exceed 3 orders of magnitude, and that it can be realistically tailored for transformation acoustic applications.