On band gap and damping of metamaterials involving negative-stiffness elements

This study proposes a viscoelastic metamaterial containing negative-stiffness elements, which exhibits both a damping enhancement effect and a tunable ultra-low frequency band gap. A dynamic model involving static large predeformation of the viscoelastic metamaterial is established based on the updated Lagrangian scheme and solved by finite element method. Numerical results show that the presence of negative-stiffness elements can reduce the frequency of the band gap and increase its damping performance by two orders of magnitude. The mechanism roots in the fact that the negative stiffness elements enable the viscoelastic metamaterials with extremely low local incremental stiffness, resulting in low-frequency local resonance and damping enhancement. This study facilitates the design of damping composites with both high stiffness and damping capacity, which are widely required in vibration and noise control. [Display omitted] •A viscoelastic metamaterial (VM) with negative-stiffness elements (NSEs) is proposed.•A nonlinear dynamic model of the VM is built based on the updated Lagrangian scheme.•The damping capacity of the VM is improved by up to two orders of magnitude.•An adjustable low-frequency band gap is obtained due to the NSEs.