Article
Acoustics
Christopher Hakoda, Cristian Pantea, Vamshi Krishna Chillara
Summary: The paper presents a simple method for designing localized regions with minimal SAW amplitude, achieved by controlling the beat phenomenon. These regions can have variable widths and be positioned consecutively. The efficacy of the proposed method for SAW wave propagation is demonstrated through supplementary simulations.
JOURNAL OF SOUND AND VIBRATION
(2021)
Article
Engineering, Mechanical
A-Li Chen, Hua-Wei Zhang, Yue-Sheng Wang
Summary: This paper derives the expression of the generalized Snell's law for modulating the Rayleigh surface wave and proposes a reconfigurable elastic metasurface based on the screw-and-nut structure to modulate the wavefront of the Rayleigh surface wave. Flexible switching between different frequencies and functions can be achieved by adjusting the screw-in depths of the nuts.
EXTREME MECHANICS LETTERS
(2023)
Article
Optics
Tian Lu, Dantian Feng, Bo Fang, Pengwei Zhou, Dong Yao, Xufeng Jing, Chenxia Li, Haiyong Gan, Yingwei He, Jinhui Cai, Zhi Hong
Summary: By using a dielectric resonance cylindrical harmonic oscillator to construct the metasurface layer, it can reduce Ohmic loss, improve reflection efficiency, and optimize the design of carpet cloaking devices. This method can effectively cover various shapes of scatterers and confirm the cloaking effect through numerical simulations of near field and far field scattering characteristics.
LASER PHYSICS LETTERS
(2021)
Article
Engineering, Mechanical
Renhao Qu, Jingwen Guo, Yi Fang, Wei Yi, Siyang Zhong, Xin Zhang
Summary: This study investigates the reflection performance of periodic acoustic metasurfaces (AMs) under sheared flow. A design method considering the mean flow profile is proposed, and two different acoustic porous metasurfaces (APMs) are numerically tested. The results demonstrate the effectiveness of the proposed method in achieving desired wavefront manipulations under different flow conditions.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Physics, Applied
Zhi-Lei Zhang, Shi-Feng Li, Xin Li, Xin-Ye Zou, Jian-Chun Cheng
Summary: This study introduces an acoustic gradient metasurface with phase modulation that converts propagating waves into surface bounded waves for energy concentration, forming standing waves under normal incidence. By placing piezoelectric composite sheets in antinode regions for acoustic energy harvesting, the output voltage maintains the same phase.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Peizheng Cao, Wenzhan Ou, Yingnan Su, Yuhang Yin, Erqian Dong, Zhongchang Song, Jiafang Li, Yu Zhang
Summary: In this study, an acoustic switch based on a spiral kirigami metasurface is designed and its performance is evaluated experimentally. The kirigami structure can control the sound propagation range, providing an alternative design strategy for acoustic metasurfaces.
PHYSICAL REVIEW APPLIED
(2022)
Article
Materials Science, Multidisciplinary
Junfeng Chen, Jianlan Xie, Jianjun Liu
Summary: This paper proposes four acoustic metasurfaces structures that can achieve sub-wavelength focusing, with small focus aberrations and almost no sidelobes. Among them, aperiodic curved metasurfaces have more efficient focusing performance and can focus at continuous operating frequencies.
RESULTS IN PHYSICS
(2021)
Article
Acoustics
Zaiwei Liu, Bin Lin, Xiaohu Liang, Anyao Du
Summary: The study reveals the significant effects of residual stress and surface damage on surface acoustic wave propagation, with residual stress causing only a slight decrease in surface wave velocity and surface damage having a significant impact on the dispersion curve.
Article
Nanoscience & Nanotechnology
Siyuan Shen, Zhaohui Ruan, Yuan Yuan, Heping Tan
Summary: This paper discusses the conditions for establishing the generalized Snell's law of refraction in all-dielectric metasurfaces, and summarizes the relationship between the highest achievable anomalous refraction efficiency and the number of nanoparticles. Additionally, conditions for establishing the polarization-independent generalized Snell's law of refraction are presented.
Article
Materials Science, Characterization & Testing
L. Xiang, S. Dixon, C. B. Thring, Z. Li, R. S. Edwards
Summary: This paper investigates the waveform distortion of electromagnetic acoustic transducers (EMATs) as the lift-off distance increases. It demonstrates the impact of induced current spatial distribution on ultrasound pulses. The study also explores the influence of coil spacing on lift-off behavior in EMATs with an array configuration.
NDT & E INTERNATIONAL
(2022)
Article
Engineering, Electrical & Electronic
Marco Faenzi, David Gonzalez-Ovejero, Giovanni Petraglia, Giuliana D'Alterio, Fabio Pascariello, Roberto Vitiello, Stefano Maci
Summary: This article presents the design, fabrication, and testing of a modulated metasurface (MTS) antenna for monopulse radar tracking at Ka-band. The antenna consists of a circular, thin grounded dielectric layer printed by a texture of metallic patches modulated in shape and size. The antenna aperture is divided into four identical quadrants each radiating independent beams. The structure has the advantages of being lightweight, low-profile, simple in feed design, and cost-effective.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Geosciences, Multidisciplinary
Jiaqi Li, Caroline Beghein, Philippe Lognonne, Scott M. McLennan, Mark A. Wieczorek, Mark P. Panning, Brigitte Knapmeyer-Endrun, Paul Davis, W. Bruce Banerdt
Summary: We have observed both minor-arc (R1) and major-arc (R2) Rayleigh waves for the largest marsquake (magnitude of 4.7 +/- 0.2) ever recorded. Along the R1 path (in the lowlands), a simple, two-layer model with an interface located at 21-29 km and an upper crustal shear-wave velocity of 3.05-3.17 km/s can fit the group velocity measurements. Along the R2 path, observations can be explained by upper crustal thickness models constrained from gravity data and upper crustal shear-wave velocities of 2.61-3.27 and 3.28-3.52 km/s in the lowlands and highlands, respectively. The shear-wave velocity being faster in the highlands than in the lowlands indicates the possible existence of sedimentary rocks and relatively higher porosity in the lowlands.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Thermodynamics
Manjeet Kumar, Pradeep Kaswan, Nantu Sarkar, Xu Liu, Manjeet Kumari
Summary: The purpose of this article is to investigate the propagation characteristics of Rayleigh waves in a nonlocal generalized thermoelastic media, including particle motion, attenuation, and phase velocity. The dispersion relation of Rayleigh waves is established using Helmholtz potentials, taking into account stress-free insulated and isothermal plane surfaces. Numerical computations are performed using MATLAB software. The thermal factors of nonlocal generalized thermoelastic materials significantly influence the particle motion, attenuation, and phase velocity of Rayleigh waves. Numerical examples are provided to examine the effects of material thermal characteristics on Rayleigh wave propagation.
INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW
(2023)
Article
Materials Science, Multidisciplinary
Tai Yi Zhang, Hui Feng Ma, Hai Lin Wang, Yan Kai Zhang, Zi Hua You, Tie Jun Cui
Summary: The study presents a method to design radiation metasurfaces that can generate spatial propagating waves with arbitrary polarizations. By customizing the phase distribution on the metasurface, the polarization of the generated SPW can be flexibly controlled.
ADVANCED MATERIALS TECHNOLOGIES
(2022)
Article
Acoustics
David Allwright
Summary: This paper demonstrates how ray theory can explain the propagation of high frequency sound waves from a point source in an inhomogeneous medium, and how Snell's law and its generalizations can be used to prove the principle of least time according to Fermat, with restrictions applied to the region free from caustics. It is also shown that if the sound speed is a concave function of position, caustics do not occur and Fermat's principle can be applied without further restriction.
JOURNAL OF SOUND AND VIBRATION
(2022)
Article
Physics, Applied
Yi Zeng, Liyun Cao, Yifan Zhu, Yan-Feng Wang, Qiu-Jiao Du, Yue-Sheng Wang, Badreddine Assouar
Summary: This research investigates the attenuation zones of an elastic metasurface composed of pillars on a substrate. By connecting the characteristics of these two zones, a seismic metasurface using only one kind of artificial structure is designed to attenuate Rayleigh waves in a specific frequency range.
APPLIED PHYSICS LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Liyun Cao, Yifan Zhu, Yanlong Xu, Shi-Wang Fan, Zhichun Yang, Badreddine Assouar
Summary: The study demonstrates the formation of a trapped mode with perfect mode conversion between flexural waves and longitudinal waves in an open elastic wave system. By achieving a quasi-bound state in the continuum, the researchers were able to approach infinite quality factor for the mode conversion. Additionally, they showed that the quality factor can be continuously tuned from quasi-BIC to BIC through the critical frequency of mode conversion, offering the possibility of achieving perfect mode conversion with an arbitrarily high quality factor.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2021)
Article
Instruments & Instrumentation
Krupali Donda, Yifan Zhu, Aurelien Merkel, Shi-Wang Fan, Liyun Cao, Sheng Wan, Badreddine Assouar
Summary: This paper introduces a deep learning-based approach to simplify the modeling process of acoustic metasurface absorbers while maintaining accuracy. Through convolutional neural networks, wide absorption spectrum response can be simulated within milliseconds. This method is attractive for applications requiring fast on-demand design and optimization of metasurface acoustic absorbers.
SMART MATERIALS AND STRUCTURES
(2021)
Article
Engineering, Mechanical
Feng Liu, Pengtao Shi, Yanlong Xu, Liyun Cao, Yizhou Shen, Zhichun Yang
Summary: The study focuses on the design of a single-phase circular meta-slab with subunits of different thicknesses to achieve total reflection of flexural waves and its application in vibration isolation. The theoretical analysis and numerical demonstrations confirm the effectiveness of the design in omnidirectional vibration isolation for practical engineering applications.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2021)
Article
Mechanics
Feng Liu, Zhichun Yang, Pengtao Shi, Yizhou Shen, Liyun Cao, Yanlong Xu
Summary: This paper proposes an ultra-broadband achromatic meta-slab (UAM) that achieves an unchanged refraction angle for incident frequencies. By utilizing subunits with gradient thickness, the UAM overcomes the issue of chromatic aberration. Experimental results demonstrate that the UAM maintains achromaticity across multiple frequencies, making it suitable for various applications such as vibration control, vibrational energy harvesting, and health monitoring.
JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME
(2022)
Article
Engineering, Mechanical
Tian Zhao, Zhichun Yang, Wei Tian, Liyun Cao, Yanlong Xu
Summary: This research proposes a new design of deep-subwavelength elastic metasurface composed of gradient force-moment resonators for abnormal reflection of flexural waves. The theoretical analysis and simulations demonstrate the effectiveness of the proposed metasurface, which has potential applications in vibration control, wave absorption, and energy harvesting.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2022)
Article
Engineering, Mechanical
Yi Zeng, Liyun Cao, Sheng Wan, Tong Guo, Yan-Feng Wang, Qiu-Jiao Du, Badreddine Assouar, Yue-Sheng Wang
Summary: Seismic metamaterials have received significant attention in the past two decades due to their ability to control seismic surface waves. In this study, a new type of seismic metamaterial with a low-frequency bandgap induced by inertial amplification is proposed to isolate seismic surface waves. Experimental results using a metamaterial plate composed of 25 unit cells demonstrate the characteristics of the bandgap induced by inertial amplification. The imaging of flexural waves by a scanning laser Doppler vibrometer shows strong attenuation effects in the bandgap caused by the metamaterial plate. The broadband attenuation is investigated using two different types of unit cells. Finally, similar structures with inertial amplification are introduced to design seismic metamaterials for isolating seismic surface waves at low frequencies.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2022)
Article
Physics, Applied
Sheng Wan, Liyun Cao, Yi Zeng, Tong Guo, Mourad Oudich, Badreddine Assouar
Summary: This letter introduces a compact low-frequency non-reciprocal metamaterial design for flexural waves. The non-reciprocal wave propagation is achieved by modulating the stiffness of the resonators and introducing a phase shift.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Yi Zeng, Liyun Cao, Sheng Wan, Tong Guo, Shuowei An, Yan-Feng Wang, Qiu-Jiao Du, Brice Vincent, Yue-Sheng Wang, Badreddine Assouar
Summary: This letter introduces a seismic metamaterial with an ultra-low frequency bandgap induced by inertial amplification. Numerical and experimental results demonstrate that the proposed metamaterial can effectively isolate seismic surface waves. Additionally, an embedded inertial amplification mechanism is introduced on a soil substrate to design a seismic metamaterial capable of attenuating seismic waves around 4Hz.
APPLIED PHYSICS LETTERS
(2022)
Article
Acoustics
Yanlong Xu, Yizhou Shen, Feng Liu, Liyun Cao, Zhichun Yang
Summary: This study investigates the flexural edge wave (FEW) on a semi-infinite isotropic elastic thin plate with a structured free edge. The dispersion relation of the modulated FEW is analytically solved by using the coupled mode theory, and the propagation characteristics of different modulated FEW modes are discussed. Numerical and experimental results demonstrate the rainbow trapping of the first-order modulated FEW and the mode conversion of the second-order modulated FEW to the bulk wave.
JOURNAL OF SOUND AND VIBRATION
(2022)
Article
Engineering, Multidisciplinary
Liyun Cao, Yifan Zhu, Sheng Wan, Yi Zeng, Badreddine Assouar
Summary: This study presents a non-Hermitian loss-modulation beam and plate model based on complex wavenumber plane for designing lossy elastic metamaterials. The high-performance absorption of the metamaterial is achieved through a combination of dissipation-radiation balance and multiple reflections. The study provides a new approach for broadband low-frequency vibration suppression and offers an effective paradigm for wave engineering in non-Hermitian elastic wave systems.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2022)
Article
Physics, Applied
Yifan Zhu, Aurelien Merkel, Liyun Cao, Yi Zeng, Sheng Wan, Tong Guo, Zihao Su, Siyuan Gao, Haohan Zeng, Hui Zhang, Badreddine Assouar
Summary: Numerically and experimentally, we demonstrate the acoustic analogue of super-Klein tunneling in a heterojunction of phononic crystals with Willis scatterers that possess pseudospin-1 Dirac cones. Unlike the pseudospin-1/2 Dirac cones, the pseudospin-1 cones require an additional flatband across the Dirac points in the band structure. The observed super-Klein tunneling in pseudospin-1 systems refers to perfect transmission at one specific frequency and all incidence angles within the energy barrier, which has significant implications for exploring the physics of pseudospin-1 quasiparticles.
APPLIED PHYSICS LETTERS
(2023)
Article
Multidisciplinary Sciences
Liyun Cao, Sheng Wan, Yi Zeng, Yifan Zhu, Badreddine Assouar
Summary: This study reports the existence of phononic skyrmions, new topological structures formed by the hybrid spin of elastic waves. The frequency-independent spin configuration of these skyrmions leads to ultra-broadband features and can be produced in any solid structure, including chip-scale ones. The experiment also demonstrates the robustness of phononic skyrmion lattices against local defects, sharp corners, and rectangular holes. This research opens up new possibilities for elastic wave manipulation and structuration through spin configuration and offers promising applications in phononic technologies.
Proceedings Paper
Acoustics
Tian Zhao, Wei Tian, Li-yun Cao, Yan-long Xu, Zhi-chun Yang
Summary: A new type of ultra-thin elastic metasurface (UEM) is proposed in this paper to manipulate flexural wave using mass-spring resonant stubs. The UEM achieves full phase control and abnormal reflection of the flexural wave through proper design of resonant stubs based on GSL. Finite element simulation results validate the effectiveness of the designed UEM, showcasing its potential in engineering applications such as vibration control and energy harvesting.
PROCEEDINGS OF THE 2020 15TH SYMPOSIUM ON PIEZOELECTRCITY, ACOUSTIC WAVES AND DEVICE APPLICATIONS (SPAWDA)
(2021)
Article
Materials Science, Multidisciplinary
Yifan Zhu, Aurelien Merkel, Krupali Donda, Shiwang Fan, Liyun Cao, Badreddine Assouar
Summary: The study introduces the concept of a nonlocal acoustic metasurface absorber using a bridge structure to improve performance, achieving ultrabroadband sound absorption with deep-wavelength thickness. The nonlocality introduces three specific effects, optimizing effective acoustic impedances, shifting Fabry-Perot resonant frequencies, and enhancing coupling effects between adjacent unit cells, contributing to improved bandwidth and efficiency.
