Ultrawide and ultralow bandgap in mutistable metamaterial via buckling deformation and bandgap coupling

This paper utilizes buckling deformation and bandgap coupling mechanisms to achieve a broader bandgap width and a reduction in bandgap frequency. A local resonance metamaterial with stiffness regulation via buckling deformation is designed. The deformation behavior and static characteristics of the buckling structure are analyzed using finite element analysis. The bandgap coupling mechanism and low-frequency behavior are further examined through Bloch theory and the transfer coefficient method. Numerical simulations show that the torsional deformation of the buckling structure induces a second stable state, where its axial stiffness is reduced by an order of magnitude compared to the initial state, resulting in a very low-frequency bandgap. Furthermore, the coupling of local resonance and Bragg bandgaps generates a wider low-frequency bandgap. This study opens a new pathway for expanding the bandwidth of low-frequency bandgaps.