Ultrawide bandgap in metamaterials via coupling of locally resonant and Bragg bandgaps

Metamaterials with wide frequency bandgaps have broad applications in engineering. In this work, a diatomic mass-in-mass metamaterial is proposed. This metamaterial can produce multiple locally resonant and Bragg bandgaps. Locally resonant and Bragg bandgaps can be coupled to produce a wider bandgap by adjusting the masses of the resonators. Furthermore, all bandgaps can be accurately coupled to produce an ultrawide coupled bandgap. A novel experimental model is designed to validate the coupled bandgap. This experimental model can accurately describe the discrete mass-spring system. This metamaterial model is manufactured via 3D printing. The bandgap coupling phenomenon can be validated experimentally. This experiment demonstrates the effect of vibration reduction in the ultrawide frequency range. The theoretically predicted transmissibility is in good agreement with the experimental transmissibility. The experiment further proved that compared with simple mass-in-mass metamaterials, the diatomic mass-in-mass metamaterial can be applied to vibration isolation in the ultrawide frequency range in engineering.