Extending and lowering bandgaps by cross-like beams phononic crystals with perforation

Aiming at the problem of low-frequency vibration and noise control in the engineering applications, a new two-dimensional phononic crystal consisting of cross-like copper beams embedded in silicon rubber plates with holes is designed and the bandgap characteristics are calculated by the finite element method. Meanwhile, the acoustic displacement fields of the bandgap edges are analyzed to clarify the mechanism of the bandgap generation and the effects of parameters variation on the band structure are discussed carefully. In addition, considering the application value of the model, the combination sealing plate structures with large size are further investigated and described. Results show that a wide low-frequency bandgap is opened and the generation of the bandgap is due to the out-plane torsional vibration of the cross-like beams. The bandgaps mainly depend on the matching degree of material and the geometry parameters of periodic hole, while the bandgaps are not quite sensitive to the thickness of plate.