Metamaterial beams with negative stiffness absorbers and rotation: band-gap behavior and band-gap merging

Two novel configurations of metamaterial beams, i.e., a monatomic and a diatomic one, are proposed in this paper through a proper combination of negative stiffness absorbers (NSAs) and rotation of flexural beams amplified by outriggers. The advantage of using the rotation rather than transversal deformation of the host beam in achieving low-frequency band gap is recognized. Then, the behavior of the rotational unit cell with NSAs are systematically investigated by concerning the influences of parameters including the negative stiffness ratio, the outrigger length, and the damping ratio. Moreover, the damping magnification effect of NSAs provides substantial damping ratios for the passband. In this way, a wider band gap can be achieved through the band-gap merging effect for the proposed diatomic configuration, where the passband between the two band gaps is capable of mitigating the waves owing to the damping magnification effect of NSAs.

Automated summary

This paper proposes two novel configurations of metamaterial beams, namely monatomic and diatomic, by combining negative stiffness absorbers (NSAs) and rotation of flexural beams. The advantage of using rotation instead of transversal deformation for achieving low-frequency band gap is acknowledged. The behavior of the rotational unit cell with NSAs is systematically investigated, considering parameters such as negative stiffness ratio, outrigger length, and damping ratio. Moreover, the damping magnification effect of NSAs provides substantial damping ratios for the passband. In this way, a wider band gap can be achieved through the band-gap merging effect in the proposed diatomic configuration, mitigating waves due to NSAs' damping magnification effect.