Article
Physics, Applied
Qing Wang, Wenjie Yu, Herui Chang, Du Qiujiao, Fengming Liu, Zhengyou Liu, Pai Peng
Summary: This work achieves total conversions between longitudinal and transverse modes using an ultrathin metamaterial plate. The plate consists of obliquely-oriented anisotropic dipolar resonators, which can convert longitudinal movement into transverse movement and vice versa. A mass-spring model is developed to analytically describe the mode conversion. The experimental results show that the conversion rate remains above 95% in varying solids.
APPLIED PHYSICS EXPRESS
(2022)
Article
Engineering, Mechanical
Zhu-Long Xu, Dan-Feng Wang, Tomohiro Tachi, Kuo-Chih Chuang
Summary: Wave mode conversion has been studied using a Kresling origami wave-mode converter that transforms longitudinal waves into torsional waves. Experimental verification shows potential applications in wave manipulation and energy distribution.
EXTREME MECHANICS LETTERS
(2022)
Article
Acoustics
Gen Li, Yan Chen, Weiting Chen, Jinming Liu, Huan He
Summary: This paper proposes a novel configuration called the local resonance Helmholtz (LRH) lattices, designed to suppress both solid-borne and air-borne sound waves simultaneously. Through numerical simulations and experimental verification, the results show the feasibility of the LRH lattices concept, opening up new possibilities for designing advanced materials with sound and vibration attenuation performances.
Article
Engineering, Mechanical
Liyun Cao, Zhichun Yang, Yanlong Xu, Zhaolin Chen, Yifan Zhu, Shi-Wang Fan, Krupali Donda, Brice Vincent, Badreddine Assouar
Summary: A new conceptual design of pillared elastic metasurface is proposed in this study to manipulate flexural waves in plates by considering constructive interference, overcoming the need for heavy grooving or drilling on plate structures. The coupling and phase shift mechanisms of transmitted waves across sub-units are analyzed to establish an analytical model for accurately predicting wave behavior. The design demonstrates deflecting and focusing functionalities, offering a new approach for broad applications of constructive interference in elastic metamaterials.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2021)
Article
Physics, Applied
Ye Jeong Shin, Hong Min Seung, Joo Hwan Oh
Summary: What makes elastic waves different from other waves is the existence of various wave modes and coupling between these modes. In this study, fluid-like elastic metasurfaces were proposed to perfectly eliminate mode coupling. Strip-type unit cells were used to design and realize elastic metasurfaces mimicking acoustic hard-wall and soft-wall. Numerical analysis and experiments were conducted to prove the validity of the designed unit cells. This study presents a more versatile metasurface by solving the mode coupling of solid elastic waves, and the designed fluid-like metasurfaces can be further utilized in studies considering the opposite phase shift characteristic.
APPLIED PHYSICS LETTERS
(2023)
Article
Acoustics
Francine Luppe, Jean-Marc Conoir, Tony Valier-Brasier
Summary: This study investigates multiple scattering effects due to a random distribution of identical spheres in elastic or poroelastic host media, considering the coexistence of longitudinal and transverse waves. It looks for the dispersion equation of plane coherent waves, and provides analytic approximations for specific solutions close to the wavenumbers in the free host under low concentration conditions. Pair-correlation effects are found to be of second order in this scenario.
Article
Physics, Applied
Di Liu, Pai Peng, Wenjie Yu, Qiujiao Du, Fengming Liu
Summary: In this study, a double-scatterer structure is proposed to achieve complete conversion of elastic bulk waves. Each unit of the elastic metamaterial slab contains a pair of scatterers with a relatively oblique direction. When attached to a semi-infinite solid background, the slab can completely convert the normal incident longitudinal wave into a reflected shear wave, or vice versa. The conversion is attributed to the in-phase coupling of the double scatterers' quadrupolar resonances, resulting in oblique displacements and horizontal displacements for reflected waves.
APPLIED PHYSICS EXPRESS
(2023)
Article
Engineering, Mechanical
Long Zhao, Ze-Qi Lu, Hu Ding, Li-Qun Chen
Summary: This study proposes an approach to explore the band energy structures of elastic metamaterials using the Hamilton principle, Bloch theorem, and finite-element method. Experimental verification on ultralow frequency metamaterials with nonlinear resonators confirms the broadband isolation of longitudinal and transverse waves.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Engineering, Mechanical
Jeseung Lee, Jooa Park, Chan Wook Park, Seung Hyun Cho, Yoon Young Kim
Summary: While retroreflection of light with single transversely polarized wave has been extensively explored, the retroreflection of a longitudinally polarized elastic wave in a solid medium is less understood. This experiment demonstrates a uniquely engineered meta-corner reflector that can retroreflect an incident longitudinal wave onto the same longitudinal wave without generating a transverse wave. The theoretical foundation for retroreflection and its application in measuring thin film thickness on a substrate is presented.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2022)
Review
Physics, Condensed Matter
Hongbo Huang, Jiujiu Chen, Shaoyong Huo
Summary: Topological elastic metamaterials with exotic topological properties open up promising engineering-oriented applications that are difficult to realize with traditional elastic metamaterials. The review covers the physical concept of topologically ordered states of elastic waves, from one-dimensional examples to two-dimensional analogues of quantum Hall, pseudospin-Hall, and valley-Hall phases, as well as recent developments in three-dimensional elastic topological phases and higher-order topological insulators. Overall, the paper provides a comprehensive overview of the flourishing research frontier on topological elastic metamaterials and highlights future directions in the field.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Review
Instruments & Instrumentation
Jeseung Lee, Yoon Young Kim
Summary: This paper provides a comprehensive review of elastic metamaterials, covering their fundamental principles and diverse applications, with a focus on their transformative impact in guided wave manipulation.
SMART MATERIALS AND STRUCTURES
(2023)
Article
Engineering, Multidisciplinary
Xingbo Pu, Antonio Palermo, Alessandro Marzani
Summary: The study proposed an analytical framework to model the effect of single and multiple mechanical surface oscillators on the dynamics of vertically polarized elastic waves propagating in a half space. Results demonstrate that the approach can accurately model elastic waves interacting with single resonators, couples of resonators, and arrays of resonators, capturing complex dynamics phenomena such as wave conversion and wave localization.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Michael Fidelis Gross, Jonathan Ludwig Guenter Schneider, Yu Wei, Yi Chen, Sebastian Kalt, Muamer Kadic, Xiaoning Liu, Genkai Hu, Martin Wegener
Summary: In classical Cauchy elasticity, 3D materials have six eigenmodes of deformation. Extremal elastic materials are classified based on the number of easy eigenmodes out of these six, leading to hexamode (N=6), pentamode (N=5), tetramode (N=4), trimode (N=3), dimode (N=2), and monomode (N=1) materials. Pentamode metamaterials have attracted significant attention, and in this study, microstructured 3D polymer-based tetramode metamaterials were designed, characterized, and compared to theoretical expectations. The potential application as a compact and broadband polarizer for acoustical phonons at ultrasound frequencies was demonstrated.
ADVANCED MATERIALS
(2023)
Article
Engineering, Mechanical
Yifei Xu, Zhigang Cao, Kemeng Cui, Yuanqiang Cai, Xingbo Pu
Summary: In this study, an original analytical formulation is proposed to investigate the interaction between seismic Love waves and a metasurface composed of tunable anti-plane resonators. The formulation utilizes the Green's function to describe the incident and scattered fields and derives a dispersion relation for hybrid Love waves using the effective medium approximation. The capabilities of the analytical formulation are demonstrated through modeling Love waves propagating across resonators, revealing complex phenomena and hybridization features.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Engineering, Mechanical
Jeseung Lee, Minwoo Kweun, Woorim Lee, Chung Il Park, Yoon Young Kim
Summary: A novel theory for perfect transmission across solid-solid interfaces is established, and a unique nonresonant anisotropic metamaterial is proposed to realize the theory. The validity of the theory is verified through experiments, and transmittance enhancement over a wide range of frequencies and incidence angles is confirmed.
EXTREME MECHANICS LETTERS
(2022)
