Cubic-symmetry acoustic metamaterials with roton-like dispersion relations

Wang, Ke; Chen, Yi; Kadic, Muamer; Wang, Changguo; Wegener, Martin

doi:10.1007/s10409-023-23020-x

Cited by 7 publications

(2 citation statements)

References 29 publications

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“…Cellular structures are constructed from a network of unit cells. [1][2][3] They can obtain a wide variety of high-performance mechanical, 4 acoustic, 5 thermal, 6 and energy absorption 7 properties by tailoring and tuning the architectural structures.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of the mechanical properties of lattice structures inspired from polycrystalline materials

Liu,

Bai,

et al. 2024

AIP Advances

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In this work, polycrystalline-like lattice structures that are inspired by the geometry of polycrystalline materials are designed. They are generated by filling periodic lattice structures into a Voronoi diagram. Then, finite element analyses of two periodic and eight polycrystalline-like lattice structures are performed to compare their mechanical properties. The numerical results show that polycrystalline-like lattice structures consisting of anisotropic rectangular X-type periodic unit cells are isotropic at the macroscale. Moreover, they have a higher specific stiffness and specific strength than periodic lattice structures under compression. Then, the energy absorption capability is investigated. Five energy absorption indicators (energy absorption, energy absorption per unit volume, specific energy absorption per unit mass, crush stress efficiency, and plateau stress) reveal that polycrystalline-like lattice structures are better energy absorption structures. Furthermore, the defect sensitivity of missing struts is discussed. The findings of this work offer a new route for designing novel lattice structures.

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Section: Introductionmentioning

confidence: 99%

Numerical investigation of the mechanical properties of lattice structures inspired from polycrystalline materials

Liu,

Bai,

et al. 2024

AIP Advances

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“…[4][5][6] Numerous further types of avoided crossing have been discussed in the literature. [7,8] Recently, the hybridization of different photon modes [9] or phonon [11][12][13][14][15][16][17][18] modes has been exploited to realize dispersion relations resembling the roton dispersion relation of sound in liquid helium-4. [19] This dispersion relation contains a broad region of backward waves, for which group velocity and phase velocity have opposite signs, indicating a negative refractive index.…”

Section: Introductionmentioning

confidence: 99%

Dispersion Engineering by Hybridizing the Back‐Folded Soft Mode of Monomode Elastic Metamaterials with Stiff Acoustic Modes

Groß,

Schneider,

Chen

et al. 2023

Advanced Materials

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In many cases, the hybridization of two or more excitation modes in solids has led to new and useful dispersion relations of waves. Well‐studied examples are phonon polaritons, plasmon polaritons, particle‐plasmon polaritons, cavity polaritons, and magnetic resonances at optical frequencies. In all of these cases, the lowest propagating mode couples to a finite‐frequency localized resonance. Herein, the unusual metamaterial phonon dispersion relations arising from the hybridization of an ordinary acoustical phonon mode with a back‐folded soft or easy phonon mode of a monomode elastic metamaterial are discussed. Conceptually, the single easy mode can have strictly zero wave velocity. In reality, its wave velocity is very much smaller than that of all other modes. Considering polymeric 3D printed elastic monomode metamaterials at ultrasound frequencies, it is shown theoretically and experimentally that the resulting pronounced avoided crossing, with a frequency splitting comparable to the mid‐frequency, leads to backward‐wave behavior for the lowest band over a broad frequency range, conceptually at zero loss.This article is protected by copyright. All rights reserved

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Observation of Chirality‐Induced Roton‐Like Dispersion in a 3D Micropolar Elastic Metamaterial

Chen

Schneider

Wang

et al. 2023

Adv Funct Materials

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A theoretical paper based on chiral micropolar effective‐medium theory suggested the possibility of unusual roton‐like acoustical‐phonon dispersion relations in 3D elastic materials. Here, as a first novelty, the corresponding inverse problem is solved, that is, a specific 3D chiral elastic metamaterial structure is designed, the behavior of which follows this effective‐medium description. The metamaterial structure is based on a simple‐cubic lattice of cubes, each of which not only has three translational but also three rotational degrees of freedom. The additional rotational degrees of freedom are crucial within micropolar elasticity. The cubes and their degrees of freedom are coupled by a chiral network of slender rods. As a second novelty, this complex metamaterial is manufactured in polymer form by 3D laser printing and its behavior is characterized experimentally by phonon‐band‐structure measurements. The results of these measurements, microstructure finite‐element calculations, and solutions of micropolar effective‐medium theory are in good agreement. The roton‐like dispersion behavior of the lowest phonon branch results from two aspects. First, chirality splits the transverse acoustical branches as well as the transverse optical branches. Second, chirality leads to an ultrastrong coupling and hybridization of chiral acoustical and optical phonons at finite wavevectors.

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Cubic-symmetry acoustic metamaterials with roton-like dispersion relations

Cited by 7 publications

References 29 publications

Numerical investigation of the mechanical properties of lattice structures inspired from polycrystalline materials

Numerical investigation of the mechanical properties of lattice structures inspired from polycrystalline materials

Dispersion Engineering by Hybridizing the Back‐Folded Soft Mode of Monomode Elastic Metamaterials with Stiff Acoustic Modes

Observation of Chirality‐Induced Roton‐Like Dispersion in a 3D Micropolar Elastic Metamaterial

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