Article
Acoustics
A. Palermo, B. Yousefzadeh, C. Daraio, A. Marzani
Summary: This study investigates the propagation of Rayleigh waves in a half-space coupled to a nonlinear metasurface, analyzing the effects of nonlinear interaction force and energy loss on wave dispersion. The research presents closed-form expressions to predict the dispersive characteristics of nonlinear Rayleigh waves, demonstrating how different types of nonlinearity affect spectral gaps in the metasurface and revealing spatial gaps induced by softening nonlinearity in dispersion curves.
JOURNAL OF SOUND AND VIBRATION
(2022)
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
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
Xingbo Pu, Antonio Palermo, Alessandro Marzani
Summary: In this study, the dynamic behavior and topological properties of quasiperiodic elastic metasurfaces are investigated. The research reveals a fractal distribution of frequency gaps and demonstrates that topologically protected edge modes can be driven by parameter variation.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Mathematics
Bogdan Felix Apostol
Summary: The elastic wave equation with seismic tensorial force is solved in a homogeneous and isotropic medium to obtain spherical-shell waves associated with primary P and S seismic waves. These waves generate secondary waves with abrupt walls and long tails on the plane surface of a half-space, propagating in the interior and on the surface. The study discusses the relevance of this seismic motion for ground motion, seismographs' recordings, and the effect of inhomogeneities in the medium.
Article
Materials Science, Multidisciplinary
Weijia Yu, Linyun Zhou
Summary: Elastic metamaterials (EMMs) have been extensively studied for their ability to control the propagation of elastic waves. However, the complex nonlinear behavior of soil poses challenges for implementing existing EMMs in practical engineering applications. To address this limitation, a seismic metamaterial surface (SMMS) is proposed for isolating Rayleigh waves over a wide frequency range. The SMMS design range is determined based on the propagation velocity of Rayleigh waves in EMMs, and a unit cell is constructed to demonstrate the desired material properties. Numerical results and scaled experiments confirm the efficacy of the new SMMS in reducing surface deformation by over 96%.
MATERIALS & DESIGN
(2023)
Review
Materials Science, Multidisciplinary
A. A. Yakovleva, I. B. Movchan, D. Misseroni, N. M. Pugno, A. B. Movchan
Summary: This article discusses the applications of microstructured materials in energy trapping, wave cloaking, and multi-structured surfaces, as well as their role in seismic response evaluation and design strategies.
FRONTIERS IN MATERIALS
(2021)
Article
Geochemistry & Geophysics
Ba Manh Le, Ting Yang, Jason P. P. Morgan
Summary: We infer the lithospheric structure beneath the Hawaiian Swell based on a joint inversion of ambient noise and teleseismic Rayleigh waves collected during the PLUME experiment. We find low-velocity anomalies beneath the lithosphere along the island chain and beneath the North Arch, consistent with the presence of melting regions and recent volcanic fields.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
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
Materials Science, Multidisciplinary
Antonio Schiavone, Xiaodong Wang
Summary: This paper presents a study on the propagation characteristics of surface waves in an elastic metamaterial with local rotational effects. It is found that the surface wave in this material exhibits dispersion, even when the effect of local rotation is relatively weak. The phase velocity of the surface wave falls between the classical Rayleigh wave and the shear wave, and particles on the free surface of the material move in an elliptical fashion similar to the classical Rayleigh wave propagation.
MATHEMATICS AND MECHANICS OF SOLIDS
(2023)
Article
Materials Science, Multidisciplinary
Weiwei Wang, Wei Guan, Yifan Dou, Yan Zhou
Summary: In this paper, an embedded seismic metamaterial with an ultra-low-frequency bandgap is proposed to analyze the attenuation of low-frequency seismic surface waves. The results show that there are vibration modes with energy concentrated in the SM and near the surface in the range of 0-1.3 Hz, while the surface wave attenuates in the range of 1.3-20 Hz.
MECHANICS OF ADVANCED MATERIALS AND STRUCTURES
(2023)
Article
Chemistry, Multidisciplinary
Yue Gou, Hui Feng Ma, Liang Wei Wu, Zheng Xing Wang, Peng Xu, Tie Jun Cui
Summary: In this study, a novel Pancharatnam-Berry (PB) coding metasurface composed of spin-decoupled elements is proposed to achieve broadband spin-selective reflections with arbitrary wavefront manipulations. The designed metasurface efficiently reflects the designated circularly polarized wave without reversing the spin state, while suppressing its orthogonally polarized wave through random diffusion. Both simulation and experiment results demonstrate the metasurface's chiral-like characteristics despite being composed of nonchiral meta-elements.
Article
Materials Science, Multidisciplinary
Xudong Liang, Alfred J. Crosby
Summary: In this study, we investigate the dynamic recoil that couples with a general nonlinear power-law interaction within a metamaterial framework. Our findings reveal that nonlinear force interactions and elastic structures in metamaterials can control the dynamic performance. We also discover a sonic vacuum response in the recoiling metamaterials, where a near-zero speed of sound is induced by strongly nonlinear interactions and zero initial prestress. Moreover, we find that the nonlinear wave speed has a non-monotonic dependence upon the strength of the power-law interaction. Our analytical model shows good agreements with experimental results, providing insights for new materials designs in high-rate applications.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(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)
Article
Optics
Hongchen Chu, Ye Zhang, Xiaoxuan Ma, Xiang Xiong, Ruwen Peng, Mu Wang, Yun Lai
Summary: In this study, we demonstrate a microwave metasurface that achieves broadband, wide-angle, and polarization-independent diffuse reflection and undistorted transmission. By changing the arrangement of meta-atoms, the wavefront in reflection can be independently manipulated, enabling a camouflaged meta-dome structure.
Article
Engineering, Mechanical
Z. Chatzopoulos, A. Palermo, S. Guenneau, A. Marzani
Summary: In this study, Love waves propagating along the surface of a heterogeneous medium are controlled by a scalar equation of the Helmholtz type under time-harmonic regime. The invariance of this equation under an in-plane arbitrary coordinate transformation is utilized to design broadband cloaks for surface defects. Dispersion analysis and time-harmonic numerical simulations validate the effectiveness of the proposed strategy, which includes the use of layered monoclinic materials to design feasible cloaks. Performance of the layered cloaks is confirmed through parametric analysis of dispersion curves and time-harmonic numerical simulations.
EXTREME MECHANICS LETTERS
(2022)
Article
Geochemistry & Geophysics
R. Zaccherini, A. Palermo, A. Marzani, A. Colombi, V. K. Dertimanis, E. N. Chatzi
Summary: Granular materials can be used to simulate and study the propagation of seismic waves in different unconsolidated porous media. This study experimentally tests an unconsolidated granular medium made of silica microbeads with a gravity-induced power-law stiffness profile, aiming to investigate the attenuation mechanisms of vertically polarized seismic waves traveling at the surface of unconsolidated substrates. The findings show that laboratory-scale physical models can be used to study the geometric spreading and material damping of seismic waves induced by soil inhomogeneity.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Acoustics
A. Palermo, B. Yousefzadeh, C. Daraio, A. Marzani
Summary: This study investigates the propagation of Rayleigh waves in a half-space coupled to a nonlinear metasurface, analyzing the effects of nonlinear interaction force and energy loss on wave dispersion. The research presents closed-form expressions to predict the dispersive characteristics of nonlinear Rayleigh waves, demonstrating how different types of nonlinearity affect spectral gaps in the metasurface and revealing spatial gaps induced by softening nonlinearity in dispersion curves.
JOURNAL OF SOUND AND VIBRATION
(2022)
Article
Engineering, Electrical & Electronic
Masoud Mohammadgholiha, Antonio Palermo, Nicola Testoni, Jochen Moll, Luca De Marchi
Summary: This paper presents a novel implementation of Frequency Steerable Acoustic Transducers (FSATs) for guided waves (GWs) inspections. The proposed Piezoceramic FSATs exploit the inherent directional properties of ultrasonic guided waves, leading to significant hardware simplification and cost reductions. Experimental validations using a Scanning Laser Doppler Vibrometer (SLDV) show improved generation of directional GWs in a host structure.
IEEE SENSORS JOURNAL
(2022)
Article
Engineering, Mechanical
Xingbo Pu, Antonio Palermo, Alessandro Marzani
Summary: In this study, the dynamic behavior and topological properties of quasiperiodic elastic metasurfaces are investigated. The research reveals a fractal distribution of frequency gaps and demonstrates that topologically protected edge modes can be driven by parameter variation.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Review
Nanoscience & Nanotechnology
Anastasiia O. Krushynska, Daniel Torrent, Alejandro M. Aragon, Raffaele Ardito, Osama R. Bilal, Bernard Bonello, Federico Bosia, Yi Chen, Johan Christensen, Andrea Colombi, Steven A. Cummer, Bahram Djafari-Rouhani, Fernando Fraternali, Pavel I. Galich, Pedro David Garcia, Jean-Philippe Groby, Sebastien Guenneau, Michael R. Haberman, Mahmoud I. Hussein, Shahram Janbaz, Noe Jimenez, Abdelkrim Khelif, Vincent Laude, Mohammad J. Mirzaali, Pawel Packo, Antonio Palermo, Yan Pennec, Ruben Pico, Maria Rosendo Lopez, Stephan Rudykh, Marc Serra-Garcia, Clivia M. Sotomayor Torres, Timothy A. Starkey, Vincent Tournat, Oliver B. Wright
Summary: This review article provides a summary of recent advances and hot research topics in nanophononics and elastic, acoustic, and mechanical metamaterials based on the authors' presentations at the EUROMECH 610 Colloquium. Unlike a conventional review, it focuses on the state-of-the-art and emerging research directions in these fields rather than historical viewpoints. The article covers basic definitions, design strategies, analysis techniques, and discussions of challenges and applications in each topic, offering valuable insights for early-career researchers and others interested in these areas.
Article
Mechanics
Yifei Xu, Xingbo Pu, Antonio Palermo, Alessandro Marzani, Yuanqiang Cai, Zhigang Cao
Summary: We propose a metabarrier composed of resonator-equipped pipes and develop an analytical formulation to investigate its mitigation performance on tunnel-induced ground-borne vibrations. Our formulation accurately models the interaction between tunnel-radiated waves and metabarrier-scattered waves, taking into account both geometric and resonance scattering effects. The proposed metabarriers can effectively shield the broadband incident waves generated by trains in tunnels.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2023)
Article
Engineering, Civil
Zubair Zahoor Banday, Xingbo Pu, Alessandro Marzani, Antonio Palermo
Summary: This work proposes a simplified analytical framework based on the multiple scattering theory to model the interaction between buildings and soil under antiplane shear waves. The framework uses a single degree-of-freedom oscillator to model each building and a viscoelastic layer on an elastic half-space to model the soil. By neglecting kinematic interaction and considering only inertial interaction, the response of buildings is modeled using a multiple scattering approach. The framework is demonstrated to be computationally inexpensive and effective in predicting the interaction between vibrating structures.
ENGINEERING STRUCTURES
(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
Acoustics
Kemeng Cui, Zhao-Dong Xu, Alessandro Marzani, Xingbo Pu
Summary: We propose a multiple scattering formulation to investigate the performance of meta-trenches, which are novel devices aimed at reducing ground motion induced by railways and/or subways. The resonators in the meta-trench contribute to improving wave mitigation in the low-frequency regime. Our analytical formulation allows for accurate modeling of the dynamics of coupled problems with a noticeable computational cost saving compared to finite element simulations.
JOURNAL OF SOUND AND VIBRATION
(2023)
Article
Engineering, Mechanical
Milad Jahangiri, Antonio Palermo, Soroosh Kamali, Mohammad Ali Hadianfard, Alessandro Marzani
Summary: In this work, a procedure is proposed to estimate the Minimum Observable Damage (MOD) by a vibration-based Structural Health Monitoring (SHM) system. The MOD is computed using Receiver Operating Characteristic (ROC) analysis and a damage index (DI) built on monitoring data/features. Numerical simulations are used to discuss the proposed idea and truss structures are considered as case studies. The proposed approach can assess the quality of the adopted DI and support the initial design of an SHM system.
PROBABILISTIC ENGINEERING MECHANICS
(2023)