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Guoliang Huang - One of the best experts on this subject based on the ideXlab platform.
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An active meta-layer for optimal Flexural Wave absorption and cloaking
Mechanical Systems and Signal Processing, 2021Co-Authors: Yangyang Chen, R. Zhu, Guoliang HuangAbstract:Abstract Flexural Wave propagation is common in thin structures and plays a key role in vibrations of structures. Designs of Flexural Wave absorbers for vibration control have been constantly pursued for decades aiming to find structures that can best balance tradeoffs between small sizes or lightweights and broadband operations. However, their absorption performance has long been evaluated on a case-by-case basis, and the theoretical limit characterizing the relationship between the absorption spectrum and the sample thickness and mass density is missing. In this study, by adopting an inequality as its electromagnetism and acoustics counterparts, the theoretical limit of Flexural Wave absorption is established. An active meta-layer composed of piezoelectric sensors and actuators with feedback control loops is proposed for optimal Wave absorption. We experimentally demonstrate the active meta-layer for optimal broadband Wave and vibration control in the beam and acting as skin cloaks of large voids in the plate. The active meta-layer is electrically programmable and scalable without losing stability. The approach proposed sheds light on designs of reconfigurable dynamic control devices and enables alternative solutions for ultrasonic sensing of complex engineering structures.
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a self adaptive metamaterial beam with digitally controlled resonators for subWavelength broadband Flexural Wave attenuation
Smart Materials and Structures, 2018Co-Authors: Yangyang Chen, Guoliang HuangAbstract:Designing lightweight materials and/or structures for broadband low-frequency noise/vibration mitigation is an issue of fundamental importance both practically and theoretically. In this paper, by leveraging the concept of frequency-dependent effective stiffness control, we numerically and experimentally demonstrate, for the first time, a self-adaptive metamaterial beam with digital circuit controlled mechanical resonators for strong and broadband Flexural Wave attenuation at subWavelength scales. The digital controllers that are capable of feedback control of piezoelectric shunts are integrated into mechanical resonators in the metamaterial, and the transfer function is semi-analytically determined to realize an effective bending stiffness in a quadratic function of the Wave frequency for adaptive band gaps. The digital as well as analog control circuits as the backbone of the system are experimentally realized with the guarantee stability of the whole electromechanical system in whole frequency regions, which is the most challenging problem so far. Our experimental results are in good agreement with numerical predictions and demonstrate the strong Wave attenuation in almost a three times larger frequency region over the bandwidth of a passive metamaterial. The proposed metamaterial could be applied in a range of applications in the design of elastic Wave control devices.
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Kirigami-based Elastic Metamaterials with Anisotropic Mass Density for SubWavelength Flexural Wave Control
Scientific reports, 2018Co-Authors: R. Zhu, Hiromi Yasuda, Guoliang Huang, Jiong YangAbstract:A novel design of an elastic metamaterial with anisotropic mass density is proposed to manipulate Flexural Waves at a subWavelength scale. The three-dimensional metamaterial is inspired by kirigami, which can be easily manufactured by cutting and folding a thin metallic plate. By attaching the resonant kirigami structures periodically on the top of a host plate, a metamaterial plate can be constructed without any perforation that degrades the strength of the pristine plate. An analytical model is developed to understand the working mechanism of the proposed elastic metamaterial and the dispersion curves are calculated by using an extended plane Wave expansion method. As a result, we verify an anisotropic effective mass density stemming from the coupling between the local resonance of the kirigami cells and the global Flexural Wave propagations in the host plate. Finally, numerical simulations on the directional Flexural Wave propagation in a two-dimensional array of kirigami metamaterial as well as super-resolution imaging through an elastic hyperlens are conducted to demonstrate the subWavelength-scale Flexural Wave control abilities. The proposed kirigami-based metamaterial has the advantages of no-perforation design and subWavelength Flexural Wave manipulation capability, which can be highly useful for engineering applications including non-destructive evaluations and structural health monitoring.
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non reciprocal Flexural Wave propagation in a modulated metabeam
Extreme Mechanics Letters, 2017Co-Authors: Hussein Nassar, Hui Chen, Andrew N Norris, Guoliang HuangAbstract:Abstract Flexural Wave propagation in an Euler–Bernoulli beam coupled to a set of spring–mass resonators is investigated in the presence of a pump Wave in the form of a space–time modulation of the beam-resonators coupling stiffness. A phase matching condition implies then that Waves incident along or against the pump Wave behave differently and gives rise in select frequency bands to one-way blocking and conversion of Waves. In particular, one-way optical–acoustic transitions are proven possible and are quantified. Various orders of magnitude of relevant physical quantities, such as gap widths and interaction lengths, are estimated so as to guide future experimental implementations.
Liyun Cao - One of the best experts on this subject based on the ideXlab platform.
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Flexural Wave absorption by lossy gradient elastic metasurface
Journal of the Mechanics and Physics of Solids, 2020Co-Authors: Liyun Cao, Zhichun Yang, Shi-wang Fan, Yifan Zhu, Zhaolin Chen, Badreddine AssouarAbstract:In this research, we systematically study the Flexural Waves diffraction. Based on the diffraction mechanism, we propose the concept of subWavelength lossy gradient elastic metasurface for Flexural Waves absorption. We theoretically reveal that the highefficiency absorption behavior stems from maximum multireflection-enhanced absorption of 0 th order diffraction, and experimentally show that robust Flexural Wave quasi-omnidirectional absorption in the frequency range extending approximately from 340 Hz to 1000 Hz (larger than 1.5 octaves). In addition, we propose a general approach which involves new physics of adjusting the arrangement sequence of subunits to suppress the 1 st diffraction mode, to further reduce the sub-Wavelength thickness of the metasurface while maintaining its high-efficiency absorption. Our designs could provide new routes to broadband vibration suppression and cancellation in lowfrequency by lossy elastic metamaterials and metasurfaces.
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asymmetric Flexural Wave transmission based on dual layer elastic gradient metasurfaces
Applied Physics Letters, 2018Co-Authors: Liyun Cao, Badreddine Assouar, Zhichun YangAbstract:Traditional asymmetric transmission of elastic Waves is mostly based on mode conversion, which presents a real challenge to get pure-mode elastic Waves. In this letter, without the aid of mode conversion, we present an innovative concept of asymmetric Flexural Wave transmission within a wide frequency band, based on dual-layer elastic Wave gradient metasurfaces. According to the generalized Snell's law, we theoretically and numerically design and experimentally demonstrate the asymmetric Flexural Wave transmission by tuning the supercell lengths of dual-layer metasurfaces. The experimental results confirm that the proposed design provides a wide effective frequency band feature, which agrees well with the theoretical analysis and predictions. Our concept offers the flexibility to control the Wave energy flow, opening the route to pragmatic applications in many fields, such as ultrasonic detection, energy harvesting, and vibration control.Traditional asymmetric transmission of elastic Waves is mostly based on mode conversion, which presents a real challenge to get pure-mode elastic Waves. In this letter, without the aid of mode conversion, we present an innovative concept of asymmetric Flexural Wave transmission within a wide frequency band, based on dual-layer elastic Wave gradient metasurfaces. According to the generalized Snell's law, we theoretically and numerically design and experimentally demonstrate the asymmetric Flexural Wave transmission by tuning the supercell lengths of dual-layer metasurfaces. The experimental results confirm that the proposed design provides a wide effective frequency band feature, which agrees well with the theoretical analysis and predictions. Our concept offers the flexibility to control the Wave energy flow, opening the route to pragmatic applications in many fields, such as ultrasonic detection, energy harvesting, and vibration control.
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Deflecting Flexural Wave with high transmission by using pillared elastic metasurface
Smart Materials and Structures, 2018Co-Authors: Liyun Cao, Zhichun Yang, Badreddine AssouarAbstract:This paper proposes an innovative and simple elastic metasurface, which is one kind of ultrathin metamaterial, to abnormally deflect normally and obliquely incident Flexural Waves. In particular, negative refraction of Flexural Wave is also realized. The proposed metasurface can support high transmission and full phase control for transmitted Waves. The metasurface is composed of three-dimensional (3D) functional units which are combined with multiple slender pillars for phase shift accumulation. The slots are filled in the 3D functional units to avoid coupling between adjacent functional units. Firstly, based on the generalized Snell's law, the metasurface in the sub-Wavelength regime is theoretically designed. Secondly, the deflecting functionality of the metasurface for incident Flexural Waves is numerically demonstrated. Finally, the deflecting functionality is verified by the corresponding experiments. The proposed metasurface has a great application potential in many fields, such as ultrasonic detection, energy harvesting, and vibration control.
Badreddine Assouar - One of the best experts on this subject based on the ideXlab platform.
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Flexural Wave absorption by lossy gradient elastic metasurface
Journal of the Mechanics and Physics of Solids, 2020Co-Authors: Liyun Cao, Zhichun Yang, Shi-wang Fan, Yifan Zhu, Zhaolin Chen, Badreddine AssouarAbstract:In this research, we systematically study the Flexural Waves diffraction. Based on the diffraction mechanism, we propose the concept of subWavelength lossy gradient elastic metasurface for Flexural Waves absorption. We theoretically reveal that the highefficiency absorption behavior stems from maximum multireflection-enhanced absorption of 0 th order diffraction, and experimentally show that robust Flexural Wave quasi-omnidirectional absorption in the frequency range extending approximately from 340 Hz to 1000 Hz (larger than 1.5 octaves). In addition, we propose a general approach which involves new physics of adjusting the arrangement sequence of subunits to suppress the 1 st diffraction mode, to further reduce the sub-Wavelength thickness of the metasurface while maintaining its high-efficiency absorption. Our designs could provide new routes to broadband vibration suppression and cancellation in lowfrequency by lossy elastic metamaterials and metasurfaces.
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asymmetric Flexural Wave transmission based on dual layer elastic gradient metasurfaces
Applied Physics Letters, 2018Co-Authors: Liyun Cao, Badreddine Assouar, Zhichun YangAbstract:Traditional asymmetric transmission of elastic Waves is mostly based on mode conversion, which presents a real challenge to get pure-mode elastic Waves. In this letter, without the aid of mode conversion, we present an innovative concept of asymmetric Flexural Wave transmission within a wide frequency band, based on dual-layer elastic Wave gradient metasurfaces. According to the generalized Snell's law, we theoretically and numerically design and experimentally demonstrate the asymmetric Flexural Wave transmission by tuning the supercell lengths of dual-layer metasurfaces. The experimental results confirm that the proposed design provides a wide effective frequency band feature, which agrees well with the theoretical analysis and predictions. Our concept offers the flexibility to control the Wave energy flow, opening the route to pragmatic applications in many fields, such as ultrasonic detection, energy harvesting, and vibration control.Traditional asymmetric transmission of elastic Waves is mostly based on mode conversion, which presents a real challenge to get pure-mode elastic Waves. In this letter, without the aid of mode conversion, we present an innovative concept of asymmetric Flexural Wave transmission within a wide frequency band, based on dual-layer elastic Wave gradient metasurfaces. According to the generalized Snell's law, we theoretically and numerically design and experimentally demonstrate the asymmetric Flexural Wave transmission by tuning the supercell lengths of dual-layer metasurfaces. The experimental results confirm that the proposed design provides a wide effective frequency band feature, which agrees well with the theoretical analysis and predictions. Our concept offers the flexibility to control the Wave energy flow, opening the route to pragmatic applications in many fields, such as ultrasonic detection, energy harvesting, and vibration control.
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Deflecting Flexural Wave with high transmission by using pillared elastic metasurface
Smart Materials and Structures, 2018Co-Authors: Liyun Cao, Zhichun Yang, Badreddine AssouarAbstract:This paper proposes an innovative and simple elastic metasurface, which is one kind of ultrathin metamaterial, to abnormally deflect normally and obliquely incident Flexural Waves. In particular, negative refraction of Flexural Wave is also realized. The proposed metasurface can support high transmission and full phase control for transmitted Waves. The metasurface is composed of three-dimensional (3D) functional units which are combined with multiple slender pillars for phase shift accumulation. The slots are filled in the 3D functional units to avoid coupling between adjacent functional units. Firstly, based on the generalized Snell's law, the metasurface in the sub-Wavelength regime is theoretically designed. Secondly, the deflecting functionality of the metasurface for incident Flexural Waves is numerically demonstrated. Finally, the deflecting functionality is verified by the corresponding experiments. The proposed metasurface has a great application potential in many fields, such as ultrasonic detection, energy harvesting, and vibration control.
Jianlin Zhao - One of the best experts on this subject based on the ideXlab platform.
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cylindrical vector beam generation in fiber with mode selectivity and Wavelength tunability over broadband by acoustic Flexural Wave
Optics Express, 2016Co-Authors: Wending Zhang, Ligang Huang, Peng Li, Biqiang Jiang, Guoquan Zhang, Jianlin ZhaoAbstract:Theoretical analysis and experimental demonstration are presented for the generation of cylindrical vector beams (CVBs) via mode conversion in fiber from HE11 mode to TM01 and TE01 modes, which have radial and azimuthal polarizations, respectively. Intermodal coupling is caused by an acoustic Flexural Wave applied on the fiber, whereas polarization control is necessary for the mode conversion, i.e. HE11x→TM01 and HE11y→TE01 for acoustic vibration along the x-axis. The frequency of the RF driving signal for actuating the acoustic Wave is determined by the phase matching condition that the period of acoustic Wave equals the beatlength of two coupled modes. With phase matching condition tunability, this approach can be used to generate different types of CVBs at the same Wavelength over a broadband. Experimental demonstration was done in the visible and communication bands.
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cylindrical vector beam generation in fiber with mode selectivity and Wavelength tunability over broadband by acoustic Flexural Wave
Optics Express, 2016Co-Authors: Wending Zhang, Ligang Huang, Biqiang Jiang, Guoquan Zhang, Feng Gao, Dong Mao, Ting Mei, Keyan Wei, Jianlin ZhaoAbstract:Theoretical analysis and experimental demonstration are presented for the generation of cylindrical vector beams (CVBs) via mode conversion in fiber from HE11 mode to TM01 and TE01 modes, which have radial and azimuthal polarizations, respectively. Intermodal coupling is caused by an acoustic Flexural Wave applied on the fiber, whereas polarization control is necessary for the mode conversion, i.e. HE11x→TM01 and HE11y→TE01 for acoustic vibration along the x-axis. The frequency of the RF driving signal for actuating the acoustic Wave is determined by the phase matching condition that the period of acoustic Wave equals the beatlength of two coupled modes. With phase matching condition tunability, this approach can be used to generate different types of CVBs at the same Wavelength over a broadband. Experimental demonstration was done in the visible and communication bands.
Jean-gabriel Minonzio - One of the best experts on this subject based on the ideXlab platform.
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dispersion characteristics of the Flexural Wave assessed using low frequency 50 150 khz point contact transducers a feasibility study on bone mimicking phantoms
Ultrasonics, 2017Co-Authors: Koussila Kassou, Youcef Remram, Pascal Laugier, Jean-gabriel MinonzioAbstract:Guided Waves-based techniques are currently under development for quantitative cortical bone assessment. However, the signal interpretation is challenging due to multiple mode overlapping. To overcome this limitation, dry point-contact transducers have been used at low frequencies for a selective excitation of the zeroth order anti-symmetric Lamb A0 mode, a mode whose dispersion characteristics can be used to infer the thickness of the Waveguide. In this paper, our purpose was to extend the technique by combining a dry point-contact transducers approach to the SVD-enhanced 2-D Fourier transform in order to measure the dispersion characteristics of the Flexural mode. The robustness of our approach is assessed on bone-mimicking phantoms covered or not with soft tissue-mimicking layer. Experiments were also performed on a bovine bone. Dispersion characteristics of measured modes were extracted using a SVD-based signal processing technique. The thickness was obtained by fitting a free plate model to experimental data. The results show that, in all studied cases, the estimated thickness values are in good agreement with the actual thickness values. From the results, we speculate that in vivo cortical thickness assessment by measuring the Flexural Wave using point-contact transducers is feasible. However, this assumption has to be confirmed by further in vivo studies.
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Dispersion characteristics of the Flexural Wave assessed using low frequency (50–150 kHz) point-contact transducers: A feasibility study on bone-mimicking phantoms
Ultrasonics, 2017Co-Authors: Koussila Kassou, Youcef Remram, Pascal Laugier, Jean-gabriel MinonzioAbstract:Guided Waves-based techniques are currently under development for quantitative cortical bone assessment. However, the signal interpretation is challenging due to multiple mode overlapping. To overcome this limitation, dry point-contact transducers have been used at low frequencies for a selective excitation of the zeroth order anti-symmetric Lamb A0 mode, a mode whose dispersion characteristics can be used to infer the thickness of the Waveguide. In this paper, our purpose was to extend the technique by combining a dry point-contact transducers approach to the SVD-enhanced 2-D Fourier transform in order to measure the dispersion characteristics of the Flexural mode. The robustness of our approach is assessed on bone-mimicking phantoms covered or not with soft tissue-mimicking layer. Experiments were also performed on a bovine bone. Dispersion characteristics of measured modes were extracted using a SVD-based signal processing technique. The thickness was obtained by fitting a free plate model to experimental data. The results show that, in all studied cases, the estimated thickness values are in good agreement with the actual thickness values. From the results, we speculate that in vivo cortical thickness assessment by measuring the Flexural Wave using point-contact transducers is feasible. However, this assumption has to be confirmed by further in vivo studies.
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Dispersion characteristics of the Flexural Wave assessed using low frequency (50–150 kHz) point-contact transducers: A feasibility study on bone-mimicking phantoms
Ultrasonics, 2017Co-Authors: Koussila Kassou, Youcef Remram, Pascal Laugier, Jean-gabriel MinonzioAbstract:Abstract Guided Waves-based techniques are currently under development for quantitative cortical bone assessment. However, the signal interpretation is challenging due to multiple mode overlapping. To overcome this limitation, dry point-contact transducers have been used at low frequencies for a selective excitation of the zeroth order anti-symmetric Lamb A0 mode, a mode whose dispersion characteristics can be used to infer the thickness of the Waveguide. In this paper, our purpose was to extend the technique by combining a dry point-contact transducers approach to the SVD-enhanced 2-D Fourier transform in order to measure the dispersion characteristics of the Flexural mode. The robustness of our approach is assessed on bone-mimicking phantoms covered or not with soft tissue-mimicking layer. Experiments were also performed on a bovine bone. Dispersion characteristics of measured modes were extracted using a SVD-based signal processing technique. The thickness was obtained by fitting a free plate model to experimental data. The results show that, in all studied cases, the estimated thickness values are in good agreement with the actual thickness values. From the results, we speculate that in vivo cortical thickness assessment by measuring the Flexural Wave using point-contact transducers is feasible. However, this assumption has to be confirmed by further in vivo studies.