Hybridization of Guided Surface Acoustic Modes in Unconsolidated Granular Media by a Resonant Metasurface

Palermo, Antonio; Krödel, Sebastian; Matlack, Kathryn H.; Zaccherini, Rachele; Dertimanis, Vasilis K.; Chatzi, Eleni; Marzani, Alessandro; Daraio, Chiara

doi:10.1103/physrevapplied.9.054026

Cited by 47 publications

(29 citation statements)

References 23 publications

(46 reference statements)

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“…We assume plane-stress conditions. To model each mass-spring resonator, we utilize a truss element with a point mass at the truss tip [39,40]. To account for periodicity, we impose Bloch-Floquet boundary conditions (BCs) on the vertical edges of the cell, along the direction of wave propagation.…”

Section: B Resonant Beads On An Elastic Substratementioning

confidence: 99%

Tuning of Surface-Acoustic-Wave Dispersion via Magnetically Modulated Contact Resonances

et al. 2019

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In this work, we propose the use of contact resonances, controlled via an external magnetic field, as a tunable platform to manipulate the dispersion of surface acoustic waves (SAWs). We exploit the analogy between surface acoustic waves in a semi-infinite medium and edge waves in a plate, to realize a compact experimental setup and to demonstrate our tuning strategy. The setup consists of a set of ferromagnetic bead resonators in contact with thin, permanent magnets and positioned at the free edge of an elastic plate. An additional set of magnets, placed at a controlled and variable distance from the beads, is used to alter the contact stiffness and natural frequencies of the bead resonators. We exploit resonances to open large-frequency band gaps via edge-wave hybridization and implement our tuning strategy to shift their frequency ranges. We predict the tuned dispersive properties of hybridized edge waves via numerical models and experimentally reconstruct them via laser vibrometry, finding excellent agreement. The use of magnetic interaction and contact mechanics as a tuning strategy for SAW systems could pave the way toward programmable devices for sensing and electronic components.

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Section: B Resonant Beads On An Elastic Substratementioning

confidence: 99%

Tuning of Surface-Acoustic-Wave Dispersion via Magnetically Modulated Contact Resonances

et al. 2019

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“…These GSAMs, confined between the surface and the in-depth layer with increasing rigidity, include horizontally (SH) and vertically (P-SV) polarized waves. A recent study [38] investigated the interaction of the P-SV acoustic modes with a metasurface of vertical oscillators. The findings revealed the hybridization of the lowest-order P-SV wave at the metasurface resonance, but an absence of surface-to-bulk mode conversion observed in homogeneous half-spaces, ascribable to the stiffness profile of the granular medium.…”

Section: Introductionmentioning

confidence: 99%

Locally Resonant Metasurfaces for Shear Waves in Granular Media

et al. 2020

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In this article the physics of horizontally polarized shear waves travelling across a locally resonant metasurface in an unconsolidated granular medium is experimentally and numerically explored. The metasurface is comprised of an arrangement of sub-wavelength horizontal mechanical resonators embedded in silica microbeads.The metasurface supports a frequency-tailorable attenuation zone induced by the translational mode of the resonators. The experimental and numerical findings reveal that the metasurface not only backscatters part of the energy, but also redirects the wavefront underneath the resonators leading to a considerable amplitude attenuation at the surface level, when all the resonators have similar resonant frequency.A more complex picture emerges when using resonators arranged in a so-called graded design, e.g., with a resonant frequency increasing/decreasing throughout the metasurface. Unlike Love waves propagating in a bi-layer medium, shear waves localized at the surface of our metasurface are not converted into bulk waves.Although a detachment from the surface occurs, the depth-dependent velocity profile of the granular medium prevents the mode-conversion, steering again the horizontally polarized shear waves towards the surface. The outcomes of our experimental and numerical studies allow for understanding the dynamics of wave propagation in resonant metamaterials embedded in vertically inhomogeneous soils and, therefore, are essential for improving the design of engineered devices for ground vibration and seismic wave containment.1

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“…The aforementioned limitations of typical base isolation systems led numerous researchers to the possibility of employing new anisotropic materials to develop innovative earthquake protection systems. Several studies present applications of such materials on foundations, introducing the term periodic foundations or metafoundations [5,6]. The potential advantage of metafoundations against conventional base isolation is in reducing the large displacement demand by reflecting the incoming energy on the interfaces and/or by dissipating energy through local resonance.…”

Section: Introductionmentioning

confidence: 99%

“…The potential advantage of metafoundations against conventional base isolation is in reducing the large displacement demand by reflecting the incoming energy on the interfaces and/or by dissipating energy through local resonance. Since the pioneering works on phononic crystals and metamaterials [7,8,9], a lot of recent interesting studies in the framework of metafoundations have been published [5,6,10,11,12,13,14,15,16]. The crucial challenge is the realisation of a sufficient band gap, targeting the main frequency content of the earthquake excitation and the characteristic frequencies of the isolated structure (normally between 0.5-10 Hz), while maintaining the dimensions of the foundation in a realistic range.…”

Section: Introductionmentioning

confidence: 99%

On the Use of Meta-Foundations for Seismic Isolation: A Practical Application for Conventional Buildings

Martakis¹,

Ntertimanis²,

Chatzi³

2019

Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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This paper presents an attempt to evaluate the feasibility and the effectiveness of an innovative foundation, which relies on the concept of local resonance, from a practical point of view. The proposed composite foundation integrates the well-established isolation system of lead rubber bearings in a layered structure form with reinforced concrete slabs, in order to tackle the inherent drawbacks of the bearing isolation. The novel foundation concept is implemented in a realistic structural geometry, designed according to the current standards, and the seismic performance is evaluated and compared against the corresponding typical base isolated and conventional stiff designed buildings. The results show that the proposed foundation concept achieves superior seismic performance in comparison to standard base isolation, providing an applicable and cost efficient solution in the framework of metafoundations. 5323 COMPDYN 2019 7 th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering M. Papadrakakis, M. Fragiadakis (eds.

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Hybridization of Guided Surface Acoustic Modes in Unconsolidated Granular Media by a Resonant Metasurface

Cited by 47 publications

References 23 publications

Tuning of Surface-Acoustic-Wave Dispersion via Magnetically Modulated Contact Resonances

Tuning of Surface-Acoustic-Wave Dispersion via Magnetically Modulated Contact Resonances

Locally Resonant Metasurfaces for Shear Waves in Granular Media

On the Use of Meta-Foundations for Seismic Isolation: A Practical Application for Conventional Buildings

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