Broadband inverted T-shaped seismic metamaterial

TL;DR

This paper introduces a novel one-dimensional inverted T-shaped seismic metamaterial with an ultra-wide first bandgap, effectively attenuating seismic surface waves and verified through large-scale field experiments.

Contribution

It proposes a new 1D inverted T-shaped seismic metamaterial with an ultra-wide bandgap, enhancing seismic wave attenuation capabilities.

Findings

The FBG consists of two parts with different wave behaviors.

Seismic surface waves are significantly attenuated in part 1.

Surface waves are converted into bulk waves in part 2.

Abstract

Seismic metamaterials (SMs) are expected to assist or replace traditional isolation systems owing to their strong attenuation of seismic waves. In this paper, a one-dimensional inverted T-shaped SM (1D ITSM) with an ultra-wide first bandgap (FBG) is proposed. The complex band structures are calculated to analyze the wave characteristics of the surface waves in the SMs. We find that the FBG of the 1D ITSM is composed of two parts; part 1 with surface evanescent waves and part 2 with no surface modes. Similar results are found in the complex band structure of the FBG of the SM consisting of periodically arranged pillars and substrate. The propagation of seismic surface waves in the 1D ITSM is different in these two frequency ranges of the FBG. In part 1, the seismic surface waves are significantly attenuated in the 1D ITSM, while in part 2, the surface waves are converted into bulk waves. Finally, the ultra-wide FBG is verified by using a kind of the two-dimensional ITSM in large-scale field experiments.