Research Article

Hierarchical large-scale elastic metamaterials for passive seismic wave mitigation

¹ CNRS, Centrale Lille, ISEN, Univ. Lille, Univ. Valenciennes, UMR 8520 - IEMN, 59000 Lille, France
² Dipartimento di Fisica, Università degli Studi di Torino, Via Pietro Giuria 1, 10125 Torino, Italy
³ Department of Mechanical Engineering, CU Boulder, 1111 Engineering Drive, UCB 427 Boulder, CO 80309, USA
⁴ Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10124 Torino, Italy
⁵ Department of Physics, University of Torino, Via Pietro Giuria 1, 10125 Torino, Italy
⁶ University of Trento, Laboratory of Bio-Inspired, Bionic, Nano, Meta Materials & Mechanics, Department of Civil, Environmental and Mechanical Engineering, Via Mesiano 77, 38123 Trento, Italy

^* e-mail: marco.miniaci@gmail.com; marco.miniaci@univlille.fr
^a Also at: Queen Mary University of London, School of Engineering & Materials Science, Mile End Road, London E1 4NS, UK.

Received: 5 November 2020
Accepted: 11 May 2021
Published online: 8 June 2021

Abstract

Large scale elastic metamaterials have recently attracted increasing interest in the scientific community for their potential as passive isolation structures for seismic waves. In particular, so-called “seismic shields” have been proposed for the protection of large areas where other isolation strategies (e.g. dampers) are not workable solutions. In this work, we investigate the feasibility of an innovative design based on hierarchical design of the unit cell, i.e. a structure with a self-similar geometry repeated at different scales. Results show how the introduction of hierarchy allows the conception of unit cells exhibiting reduced size with respect to the wavelength while maintaining the same or improved isolation efficiency at frequencies of interest for earthquake engineering. This allows to move closer to the practical realization of such seismic shields, where low-frequency operation and acceptable size are both essential characteristics for feasibility.