On the feasibility of structural metamaterials for seismic-induced vibration mitigation

Abstract

This paper summarizes recent efforts toward development of locally resonant metamaterial structures for seismic isolation purposes. The metamaterial structure forms a blind zone in the frequency domain, inhibiting the propagation of waves characterised by frequencies lying within this range. The feasibility of fashioning such systems in the [0.5, 5] Hz frequency band, linked to earthquake induced response, is here explored. An analytical and numerical investigation is undertaken relying on Bloch's theory and classical vibration analysis. The analysed case-studies pertain to both one-dimensional and two-dimensional mass-in-mass lattice systems investigated for overlapping sub-bands. On the basis of the offered analysis, a basic unit cell design is proposed, and a parametric study is carried out revealing the critical influence of the external-to-internal stiffness ratios adopted for the unit cell design. A further discussion is offered with respect to limitations and extensions of the proposed designs.