Abstract:
Locally resonant metamaterials avoid the dilemma of Bragg scattering periodic structure applicated at low frequencies and achieve the manipulation of large-wavelength elastic waves with subwavelength size structure. Therefore, in this study, a buried metabarrier is proposed by periodically arranging the resonators along the depth direction, and its attenuation performance against low-frequency seismic surface waves is investigated. Based on the concept of the effective mass of locally resonant metamaterials and the effective medium method, the dispersion equations of Rayleigh waves in fully resonant half-space and finite buried metabarrier are derived, and the corresponding computational programs are programmed. 2D unit cell finite element models of fully resonant half-space and finite buried metabarrier, developed in COMSOL MULTIPHYSICS, are designed to solve the numerical dispersion relation by characteristic frequency analysis and confirm the effectiveness of the theoretical analysis method. Simultaneously, the influence of buried metabarrier depth on frequency bandgap width is studied by numerical method. The transmission analysis model of finite buried metabarrier and Bragg scattering periodic wave barrier is established. The dynamic responses of the two barriers under harmonic excitation and ground motion are investigated by frequency domain analysis and transient analysis. The results show that the buried metabarrier has a lower initial frequency of bandgap and flexible design and has a significant suppression effect on surface ground motion, which is expected to be applied in engineering practice as a new seismic isolation technology.