A multifaceted study of embedded seismic metamaterials : bridging unit cells, bandgaps, and multi-domain characteristics

Abstract

Seismic metamaterials (SMs) are an emerging technology for seismic mitigation. Existing studies have primarily focused on optimizing the configuration of SM unit cells to broaden the bandgap. However, the bandgap, as a highly idealized indicator, is built upon the assumption of a fully periodic arrangement of unit cells and cannot quantify the actual seismic attenuation of SMs under many practical circumstances. System-level approaches, such as time-domain and frequency-domain analyses, offer more pragmatic evaluations of the SM performance. Nevertheless, the complex interrelationships among these measures pose significant challenges for effective assessment. Therefore, this research aims to elucidate the intrinsic correlations among unit cell configuration, bandgap, and multi-domain characteristics, including frequency transmission and time transient behavior. A fully embedded SM is developed for in-depth investigations. High-fidelity finite element models are developed to characterize the bandgaps and multi-domain responses of the SM. Time transient analysis incorporating actual earthquake-induced ground motion data indicates the SM's ability to attenuate real seismic waves. The attenuation spectrum extracted from the time transient analysis closely corresponds with that observed in frequency transmissions, regardless of SM operational conditions. Additionally, while bandgap analysis is efficient, relying solely on the bandgap is insufficient for quantifying SM wave attenuation performance. On the other hand, a combination of multi-domain analyses provides a more comprehensive metric for performance assessment, thereby contributing to future SM design.