Composite pentamode metamaterials with low frequency locally resonant characteristics

Abstract

Locally resonant phononic crystals have excellent low-frequency characteristics and can result in a small size controlling a long wavelength. Based on the locally resonant phononic crystal theory, locally resonant pentamode metamaterials with composite materials are proposed and studied. The acoustic band frequencies of the locally resonant pentamode metamaterials were found to be two orders of magnitude smaller than those of conventional Bragg-Scattering pentamode metamaterials with the same lattice constant. Therefore, the single-mode frequency regions and locally resonant acoustic bandgaps which are under 110 Hz can be obtained by locally resonant pentamode metamaterials with a centimeter-scale lattice constant. The figure of merit can be increased by 60.78%–138.08%. This kind of locally resonant pentamode metamaterial opens a new path for applications in low-frequency acoustic cloaking and control of long wavelengths using small structure dimensions.

A Review of Research on Seismic Metamaterials

“…Therefore, the single-mode frequency regions and locally resonant acoustic bandgaps which are under 110 Hz can be obtained by locally resonant pentamode metamaterials with a centimeter-scale lattice constant and opens a new path for applications in lowfrequency acoustic cloaking and control of long wavelengths using small-structure dimensions. [124] Cai et al proposed a method for tuning the first phononic bandgaps of locally resonant pentamode metamaterials. The method is based on the equivalent relationship between the locally resonant mode at the lower edge of the first phononic bandgaps and a springmass system.…”

“…However, the composition of the seismic waves is complex and the direction of the incident is uncertain. Although some scholars have conducted 3D structural research considering waves in any given direction, most of the existing studies are based on the 2D simplified model to analyze the propagation of waves . The ignored coupling modes outside the plane may lead to the estimation deviation of band structure.…”

“…Wang et al proposed and studied the local resonant pentamode metamaterials with composite materials, whose resonance frequencies are two orders of magnitude smaller than those of conventional Bragg scattering pentamode metamaterials with the same lattice constant, as shown in Figure . Therefore, the single‐mode frequency regions and locally resonant acoustic bandgaps which are under 110 Hz can be obtained by locally resonant pentamode metamaterials with a centimeter‐scale lattice constant and opens a new path for applications in low‐frequency acoustic cloaking and control of long wavelengths using small‐structure dimensions . Cai et al proposed a method for tuning the first phononic bandgaps of locally resonant pentamode metamaterials.…”

“…b) A composite material pentamode structure consisting of two different materials. Reproduced with permission . Copyright 2017, American Institute of Physics.…”

Tunable wave propagation by varying prestrain in tensegrity-based periodic media

“…Artificially engineered lattices have been the subject of extensive research over the past decade due to their unique static and dynamic properties [2,3]. Examples include pentamode lattices with zero shear modulus [4,5], auxetic lattices with negative Poisson's ratio [6,7] and hexagonal lattices featuring frequency bandgaps [8,9]. These lattices fall under the category of metamaterials and metastructures that have potential for unprecedented control over the effective structural properties through the careful design of their microstructure.…”