Large Scale Simulations of Metamaterials for Seismic Waves Mitigation
Date: 4/25/2019
Time: 06:00 PM
Room: Grand Ballroom
The so-called Bloch-Floquet periodic boundary conditions are often used in conjunction with metamaterials to extract dispersion curves and attenuation profiles from a single unit-cell as if the metamaterial was infinitely periodic. Practical applications however rarely meet this condition and require the metamaterial to be modeled in a more physically accurate way. Seismic metamaterials fall perfectly in this category and are an ideal case study. In this field, metabarriers and metafoundations to shield structures from seismic waves and groundborne vibrations through a periodic arrangement of resonators are increasingly attracting attention. So far a handful of design have been proposed and while a metabarrier differs from a metafoundation in that it does not need to withstand heavy vertical loads, both rely upon the same resonant physics. Local resonances between adjacent unit-cell create bandgaps allowing waves to be reflected away from the protected structure.
The performances in terms of attenuation and bandwidth of a seismic metamaterial are directly underpinned by the size and kinematics of each resonator and also by the number of unit-cell constituting the metamaterial. Since in civil engineering one aims at reducing volumes and masses while maintaining the functionalities, the total number of resonators and their mass play a key role on the applicability of metamaterials for metabarriers and metafoundations. Here, after setting up a detailed 3D spectral element model containing the metabarrier/metafoundation, the structure to protect, the soil and the seismic wavefield, a sensitivity analysis to guide and optimize the metamaterial design is presented and discussed. In particular the effect of graded or random resonator distributions and the ground-resonators coupling are found to be among the most influent parameters on the metabarrier/ metafoundation attenuation capacity
Presenting Author: Andrea Colombi
Authors
Andrea Colombi andree.colombi@gmail.com ETH Zurich, Zurich, , Switzerland Presenting Author
Corresponding Author
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Rachele Zaccherini zaccherini@ibk.baug.ethz.ch ETH Zurich, Zurich, , Switzerland |
Large Scale Simulations of Metamaterials for Seismic Waves Mitigation
Category
Metamaterials, Resonances and Seismic Wave Mitigation, an Emerging Trend in Seismology