Attenuation effects of seismic metamaterials based on local resonance and Rayleigh wave dispersion phenomena

Abstract

Locally resonant metamaterials have successfully addressed the challenges posed by Bragg scattering-type periodic structures in low-frequency applications, opening new avenues for the development of advanced seismic systems. However, the prevalent semi-embedded seismic metamaterials still face issues such as narrow attenuation band gaps and complex vibration modes. This paper introduces a novel type of seismic metamaterial (SM) composed of an external steel enclosure and an upper spiral beam resonator system. To avoid complex vibration modes, the upper structure is integrated into a single unit through a bottom steel plate, and its band gaps are calculated using dispersion analysis and acoustic cone methods to clarify the attenuation range of the seismic metamaterial. By parameter design, the designed seismic metamaterial can achieve wideband seismic wave attenuation from 2.68 Hz to 16 .34Hz. Moreover, the seismic metamaterial still exhibits attenuation effects even in the absence of resonators. This attributed to Rayleigh wave dispersion in a double-layer medium, which induces inverse dispersion, transforming Rayleigh waves into body waves and further enhancing the damping effect. Finally, time-domain analysis elucidated the dynamic response of the seismic metamaterial, substantiating the validity of the study. We hope this research can promote the engineering application of common building materials in the shielding of seismic waves at deep sub-wavelength frequencies.