Wide band-gap seismic metastructures

Metamaterials exploit local resonances to reflect acoustic signals with wavelengths well above the characteristic size of the material’s structure. This has allowed obtaining materials that present low-frequency (albeit narrow) band gaps or devices for optical and acoustic cloaking. In this work, we propose to use an array of resonating structures (herein termed a “metastructure”) buried around sensitive buildings to control the propagation of seismic waves. These seismic metastructures consist of arrays of cylindrical tubes containing a resonator suspended by soft bearings. To obtain broadband attenuation characteristics, each resonator in the array is designed to exhibit a different eigenfrequency. We study the response of these systems using numerical analysis and scaled (1:30) experiments. We target wave mitigation in the infrasound regime (1–10 Hz), a range of frequencies relevant for the protection of large buildings.

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