A novel quasi-zero-stiffness metamaterial plate with tunable bandgap

As an artificially constructed periodic material, metamaterials have a widely potential application in the field of low-frequency vibration isolation. However, the focus of attention has been mainly on the isolation of one-dimensional longitudinal waves along the axial direction of the structure, and there is less research on the suppression of bending waves. To address this issue, a novel quasi-zero-stiffness metamaterial plate with adjustable bandgap is proposed in this paper, consisting of two outer skins and a cellular core composed of unit cells in the form of truncated conical shells, whereas the bandgap characteristics and propagation mechanism of bending waves along the metamaterial are investigated under three different loading modes of surface excitation, center excitation, and apex excitation, respectively. The results show that the metamaterial plate has a favorable low-frequency attenuation performance and excellent adjustable bandgap characteristics for different patterns of vibration forces, exhibiting a reliable low-frequency and broadband vibration isolation capability. Additionally, the influence of plate thickness, resonant mass and material damping on the bandgap characteristics is also revealed. Aiming at the low-frequency vibration isolation problem under different excitation modes, a novel approach is provided in this study, making it possible to contribute to other researches in this field.