Study on the complex band gap characteristic of controllable metastructure

The controllable metastructure can adjust the band gap characteristic of the structure according to the target requirements, and realize the controllable adjustment of structural vibration reduction under different working conditions. It has a wide application prospect in aerospace, rail transit and other engineering fields. A new controllable metastructure configuration was proposed, which can simultaneously generate two kinds of band gaps, local resonance and Bragg scattering. The band gap can be effectively controlled by applying displacement. The finite element model of the structure was established by COMSOL software. The energy band distribution of four controllable metastructure configurations and the regulation of band gap characteristics under external displacement excitation were studied. The vibration transmission characteristics of the structure were tested and compared with the numerical results. The results show that the four-oscillator composite band gap controllable metastructure has three complete band gaps in the range of 0-800 Hz. The first-order band gap range is as low as 134.48-287.53 Hz, the second-order band gap range is 307.26-447.81 Hz, and the third-order band gap range is 662.44-679.43 Hz. The band gap characteristics of four cell configurations were compared and analyzed. In a certain frequency range, as the number of oscillators increases, the number of band gaps decreases, the bandwidth increases, and the band gap position gradually moves up. The application of structural displacement can effectively control the structural band gap. As the displacement value increases, the low-frequency local resonance band gap in the structure changes little, and the center frequency of the Bragg band gap gradually moves up, and a new band gap appears. This study shows that the structure has good vibration reduction characteristics in the band gap range. The results show that the designed composite band gap controllable metastructure can realize the regulation of the composite band gap, which provides a useful reference for the research of metastructure vibration reduction design.