Abstract Critical concepts from three different fields, elasticity, plasmonics and metamaterials, are brought together to design a metasurface at the geophysical scale, resonant metawedge, control seismic Rayleigh waves. Made of spatially graded vertical subwavelength resonators on an elastic substrate, metawedge can either mode convert incident surface waves into bulk shear or reflect creating “seismic rainbow” effect analogous optical rainbow for electromagnetic metasurfaces. Time-domain...

Abstract We explore the thesis that resonances in trees result forests acting as locally resonant metamaterials for Rayleigh surface waves geophysics context. A geophysical experiment demonstrates a wave, propagating soft sedimentary soil at frequencies lower than 150 Hz, experiences strong attenuation, when interacting with forest, over two separate large frequency bands. This is interpreted using finite element simulations demonstrate observed attenuation due to bandgaps are arranged...

Abstract. We present a methodology to compute 3-D global seismic wavefields for realistic earthquake sources in visco-elastic anisotropic media, covering applications across the observable frequency band with moderate computational resources. This is accommodated by mandating axisymmetric background models that allow multipole expansion such only 2-D domain needed, whereas azimuthal third dimension computed analytically on fly. dimensional collapse opens doors storing space–time disk can be...

We consider the canonical problem of an array rods, which act as resonators, placed on elastic substrate; substrate being either a thin plate or half-space. In both cases flexural plate, Rayleigh surface, waves in interact with resonators to create interesting effects such effective band-gaps for surface filters that transform into bulk waves; these have parallels field optics where sub-wavelength metamaterials, and metasurfaces, at respectively. Here we carefully analyse this by extracting...

Abstract In elastic wave systems, combining the powerful concepts of resonance and spatial grading within structured surface arrays enable resonant metasurfaces to exhibit broadband trapping, mode conversion from (Rayleigh) waves bulk (shear) waves, frequency selection. Devices built around these allow for precise control often with structures that are subwavelength, utilise Rainbow trapping separates signal spatially by frequency. yields large amplifications displacement at resonator...

We amalgamate two fundamental designs from distinct areas of wave control in physics, and place them the setting elasticity. Graded elastic metasurfaces, so-called metawedges, are combined with now classical Su-Schrieffer-Heeger (SSH) model field topological insulators. The resulting structures form one-dimensional graded-SSH-metawedges that support multiple, simultaneous, topologically protected edge states. These robust, enhanced localised modes leveraged for applications energy harvesting...

Recent years have heralded the introduction of metasurfaces that advantageously combine vision sub-wavelength wave manipulation, with design, fabrication and size advantages associated surface excitation. An important topic within is tailored rainbow trapping selective spatial frequency separation electromagnetic acoustic waves using graded metasurfaces. This dependent segregation has implications for energy concentrators harvesting, sensing filtering techniques. Different demonstrations...

This work proposes a graded metamaterial-based energy harvester integrating the piezoelectric harvesting function targeting low-frequency ambient vibrations (<100 Hz). The combines metamaterial with beam-like resonators, patches, and self-powered interface circuit for broadband high-capability harvesting. Firstly, an integrated lumped parameter model is derived from both mechanical electrical sides to determine power performance of proposed design. Secondly, thorough numerical simulations...

In this paper, we incorporate the effect of nonlinear damping with concept locally resonant metamaterials to enable vibration attenuation beyond conventional bandgap range. The proposed design combines a linear host cantilever beam and periodically distributed inertia amplifiers as local resonators. geometric nonlinearity induced by causes an amplitude-dependent effect. Through implementation both modal superposition numerical harmonic methods Alternating Frequency Time continuation...

Deep sub-wavelength focusing has been demonstrated for locally resonant metamaterials using electromagnetic and acoustic waves. The elastic equivalents of such objects are made resonating beams fixed to a two-dimensional plate, as presented here. Independent random or regular arrangement the resonators, metamaterial shows large bandgaps that independent incident wave direction. Numerical simulations demonstrate insertion defect in layout, shorter resonator, creates strong amplification...

This paper deals with the numerical design of a directional invisibility cloak for backward scattered elastic waves propagating in thin plate (A0 Lamb waves). The is based on set resonating beams that are attached perpendicular to and arranged at sub-wavelength scale ten concentric rings. exotic effective properties this locally resonant metamaterial ensure coexistence bandgaps cloaking certain beam configurations over large frequency band. best was obtained when resonators' length decreases...

In metamaterial science local resonance and hybridization are key phenomena strongly influencing the dispersion properties; metasurface discussed in this article created by a cluster of resonators, subwavelength rods, atop an elastic surface being exemplar with these features. On metasurface, band-gaps, slow or fast waves, negative refraction dynamic anisotropy can all be observed exploring frequencies wavenumbers from Floquet-Bloch problem using Brillouin zone. These extreme...

In this work we employ additive manufacturing to print a circular array of micropillars on an aluminium slab turning its top surface into graded index metasurface for acoustic waves (SAW). The reproduces Luneburg lens capable focusing plane SAWs point. profile is obtained by exploiting the dispersion properties arising from well-known resonant coupling between (0.5 mm diameter and variable length ∼3 mm) propagating in substrate. From analytical formulation metasurface's curves, slow phase...

Abstract Motivated by the importance of lattice structures in multiple fields, we numerically investigate propagation flexural waves a thin reticulated plate augmented with two classes metastructures for wave mitigation and guiding, namely metabarriers metalenses. The cellular architecture this invokes well-known octet topology, while metadevices rely on novel customized octets either comprising spherical masses added to midpoint their struts or variable node thickness. We determine...

Abstract Metamaterials are artificially structured media that exibit properties beyond those usually encountered in nature. Typically they developed for electromagnetic waves at millimetric down to nanometric scales, or acoustics, centimeter scales. By applying ideas from transformation optics we can steer Rayleigh-surface solutions of the vector Navier equations elastodynamics. As a paradigm conformal geophysics creating, design square arrangement Luneburg lenses reroute Rayleigh around...

In this article, interpretation of an equivalent to a macroseismic intensity survey, performed in three identical stand-alone buildings located Grenoble, France, after M L 4.1 earthquake, reveals clustering effect, resulting different levels perception seismic loading by inhabitants.The effect is confirmed using numerical simulation; the variation response building middle cluster depends on azimuth source relative cluster.The major splitting its resonance frequency, accompanied decrease...

A comprehensive numerical study on the performance of a novel nonlinear foundation consisting alternating layers lead rubber bearings and concrete slabs is presented in this article. The design combines established load bearing capacity commercial with wave propagation inhibition by means Bragg scattering periodic structures. This solution substantially reduces structural demand under ground motion excitation without compromising during operational loading. evaluated through response history...

The dispersion curves of a cluster closely spaced rods supported by thin plate are characterised subwavelength bandgaps and slow group velocities induced local resonance effects. A recent analytical study [Williams, Roux, Rupin, Kuperman (2015). Phys. Rev. B 91, 104307], has shown how the velocity branch depends, amongst other parameters, on height that make up cluster. Such metamaterial, offering easy-to-tune spatial gradients, is perfect candidate for building gradient index lenses such as...