Broadband seismic metamaterial with an improved cylinder by introducing plus-shaped structure

Abstract The narrow bandgap of a seismic metamaterial dramatically limits its application in attenuating seismic waves for securing buildings. This research proposes an improved cylinder-type seismic metamaterial by introducing plus-shaped to widen the bandgap. The propagation of seismic waves through a three-dimensional sample of seismic metamaterial is calculated to show its efficiency of the earthquake shielding using the finite-element method based on Floquet-Bloch theory. By comparison to the common seismic metamaterial consisting of simple cylinder structures, it is found that our metamaterial based on cylinder with plus-shaped structures can yield a three times relative bandgap width for seismic surface waves, which is more suitable for practical applications. Moreover, the bandgap depends on the constraint of geometric parameters and elastic parameters, and can be easily tuned to higher frequency for other phenomena such as vibration and noise attenuation by tailoring those parameters.