A sandwich meta-structure plate with ultra-low-frequency broadband vibration bandgap

A quasi-zero-stiffness-lever-inertial-amplification coupled sandwich meta-structure plate (QZS-LIA CSMP) is proposed to achieve an ultra-low-frequency broadband vibration bandgap (below 10 Hz) for sandwich meta-structure plates. The dispersion relation and transmission characteristics of the proposed structure are investigated. It is found that the QZS-LIA CSMP can open a bandgap from 4.3 Hz to about 10 Hz. The bandgap opening frequency is reduced by 83.8%, and the bandgap width is increased by 33% compared to the conventional meta-structure plate. The main mode shape of the proposed oscillator, as determined by the bandgap formation mechanism, is that the lever amplifies the mass while compressing the QZS model, reducing stiffness without applying a pre-displacement, while keeping the actual mass and stiffness constant. The double oscillators enhance the suppression force of the sandwich periodic substrate, which increases the bandgap width. The proposed structure is lightweight, load-bearing, and has a broadband vibration bandgap at ultra-low frequencies. It provides a solution for ultra-low-frequency vibration control of sandwich meta-structure plates.