Subwavelength partial-embedded seismic metamaterial with wide working frequency: Numerical simulation and experiment

Considering the massive disasters caused by earthquakes, artificial materials and structures deemed to control the propagation of surface seismic waves have always been in great demand and have been subject to intensive research in recent decades. In an effort put forward in this paper, a local resonance type seismic shield with varying resonator mass is introduced. The resonators are partially embedded in the ground to ensure strong connections. Establishing the surface wave shielding facts by using laboratory-scale experiment and complemented with full-scale finite element simulations, the effective attenuation on surface seismic waves by either seismic rainbow trapping or mode conversion is demonstrated. By presenting unconventional dispersion relation and von Mises stress field map of the buildings with and without protection of the seismic shield, the occurring and working mechanisms of local trapping and mode conversion are established and explained in a comprehensive study. Frequency spectrums of transmission ratio are plotted to validate the broadband efficacy of gradient designing due to the superposition of bandgaps. Subsequently, a 1:400 laboratory-scale experiment using clay and 3D printing resonators is conducted to demonstrate surface shear wave mitigation. Finally, the time history signals of two real earthquakes are applied to the model and a significant reduction on the acceleration amplitude is observed in the wave attenuation region. Thanks to the subwavelength size and feasible structure, this local resonance type seismic shield is economical and convenient to construct, and thus it provides great application potential for regional protection of buildings and infrastructures against damages due to seismic and other forms of surface waves. © 2025 Elsevier Ltd.