Observation of triple-branch valley topological edge states and abnormal refraction in elastic phononic crystal plates

Yuan, Weitao; Zhao, Jinfeng; Zhang, Yuxuan; Huang, Yao; Kang, Guozheng

doi:10.1016/j.ijmecsci.2023.108825

Cited by 6 publications

(2 citation statements)

References 55 publications

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“…Meanwhile, based on the analog of QVHE, the valley edge transport of the zero-order asymmetric (A 0 ) Lamb mode in the thin plate was obtained by Wang and Mei [39]. For the valley topological refraction of Lamb wave, Yuan et al [40], studied the three-branch valley edge state and its rich refraction behavior on a single-valley chiral PnC plate with doublesided symmetric columns. Yang et al [41], proposed a PnC plate that can realize QVHE by adjusting the mass variation of the resonator, and discussed various topological refraction beams for flexural wave in subwavelength scale.…”

Section: Introductionmentioning

confidence: 99%

Robust transport and topological valley refraction of fundamental symmetric lamb waves in perforated phononic crystal plates

Li,

Huo,

Yang

et al. 2024

Phys. Scr.

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Lamb waves can be divided into antisymmetric Lamb waves (type A) and symmetric Lamb waves (type S), which are widely used in health monitoring of engineering structures and nondestructive evaluation of materials. However, due to the fact that each mode of Lamb wave has the setting group velocity in a certain bandwidth range, it is easy to cause the aliasing of multi-mode Lamb waves, partly limiting the application scenarios of Lamb wave. In this paper, a hexagonal lattice meta-structure is designed and the zero-order symmetric (S0) Lamb wave in a finite thickness plate is successfully separated. By breaking the spatial C3v symmetry, a valley topological phononic crystal (PnC) plate for the pure S0 mode is constructed, and its robust topological transports are demonstrated. Firstly, the valley topological phase transition of S0 mode is realized by changing the angle of scatterer in PnC plate and the valley edge state of S0 mode is obtained. Furthermore, by introducing structural mismatch, it is verified that the edge state of S0 mode is robust to various bends and defect. Finally, by changing the material property of the terminal, the valley refraction with different directionality is realized. The results offer a route to individually study the symmetric modes of Lamb waves, and have potential application prospects in rapid and accurate ultrasonic nondestructive testing based on Lamb waves.

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Section: Introductionmentioning

confidence: 99%

Robust transport and topological valley refraction of fundamental symmetric lamb waves in perforated phononic crystal plates

Li,

Huo,

Yang

et al. 2024

Phys. Scr.

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“…The incorporation of topological phases within mechanical metamaterials has enabled defect-immune elastic wave manipulation 1,2 . The topological mechanical metamaterials developed thus far have overwhelmingly focused on confining elastic waves at the boundaries and interfaces of conventional integer-dimensional (1D, 2D, and 3D) periodic mechanical lattices [3][4][5][6] . Recently, topological phases have been derived and theoretically investigated in fractal quantum systems [7][8][9][10][11][12] .…”

Section: Introductionmentioning

confidence: 99%

Uncovering higher-order topological states in fractal mechanical metamaterials

Dorin,

Wang

2024

Active and Passive Smart Structures and Integrated Systems XVIII

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Recently, researchers have incorporated topological phases into mechanical metamaterials to facilitate defect-immune elastic wave and vibration manipulation. The topological mechanical metamaterials developed thus far have achieved extraordinary wave control capabilities through the construction of robust elastic waveguides at the boundaries and interfaces of 1D, 2D, and 3D periodic mechanical lattices. Given the overwhelming focus of previous research on traditional integer-dimensional mechanical architectures, an unexplored opportunity exists to investigate the emergence of topological phases in fractal mechanical metamaterials, which have a non-integer dimension and exhibit self-similarity across multiple scales. This research addresses the unexplored opportunity and advances the state of the art through the synthesis of a 1.89D fractal mechanical metamaterial that harnesses higher-order topological phases to enable multifaceted elastic wave and vibration control. The proposed fractal topological mechanical metamaterial is a thin plate with embedded torsional spring-mass resonators that are arranged into the pattern of a 1.89D Sierpiński carpet. A numerical eigenfrequency analysis uncovers coexisting topological corner and edge states that trap wave energy at the myriad corner and edge interfaces available in the 1.89D fractal. The outcomes from this study provide insight into the attainment of higher-order topological states in fractal metamaterials that localize elastic waves and vibrations across various locations and frequencies, opening the door for future research of topological phases in mechanical metamaterials with fractal architectures.

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