Perforated elastic metamaterials (EMMs) comprising periodic distribution of holes have recently attracted growing attention due to relatively simple fabrication process and unusual physical properties. Rational design of perforation configuration for practical applications in low-frequency vibration mitigation is challenging and important. In this study, a novel type of perforated EMMs with two bandgap formation mechanisms (i.e., Bragg scattering and local resonance) is proposed for low-frequency and broadband wave attenuation. Four concentric spiral holes are introduced into each matrix material of the conventional EMMs plate with mutually orthogonal rectangular holes. The analysis of bandgap formation mechanism indicates that the coiled waveguide introduced by the spiral holes enhances the wave scattering in the matrix material, and that the wave scattering in the divided matrix material by the orthogonal rectangular holes couples the local resonance modes formed by the spiral holes, where the coupling modes lead to the generation of the coupling bandgap and the improvement of wave attenuation. Both experiments and numerical analyses demonstrate that the proposed metamaterials can create multiple bandgaps in the sub-wavelength frequency domain compared to the metamaterials with single-type holes, which include two Bragg bandgaps with a reduced frequency of 76%, two overlapping bandgaps with local resonance dominating, and two deaf bands.

由于制造过程相对简单和异常的物理性能，包括孔的周期性分布的穿孔弹性超材料（EMM）最近引起了越来越多的关注。在低频减振中的实际应用中，合理设计射孔配置具有挑战性和重要意义。在这项研究中，针对低频和宽带波衰减，提出了一种具有两种带隙形成机制（即布拉格散射和局部共振）的新型穿孔EMM。将四个同心螺旋孔引入具有相互正交的矩形孔的常规EMM板的每种基体材料中。对带隙形成机理的分析表明，螺旋孔引入的螺旋形波导增强了基体材料中的波散射，正交矩形孔在分裂的基体材料中的波散射耦合了由螺旋孔形成的局部共振模，其中耦合模导致耦合带隙的产生和波衰减的改善。实验和数值分析均表明，与具有单型孔的超材料相比，所提出的超材料可以在亚波长频域中创建多个带隙，其中包括具有降低的频率为76％的两个布拉格带隙，两个具有局部共振的重叠带隙主宰，还有两个聋人乐队。耦合模式导致耦合带隙的产生和波衰减的改善。实验和数值分析均表明，与具有单型孔的超材料相比，所提出的超材料可以在亚波长频域中创建多个带隙，其中包括具有降低的频率为76％的两个布拉格带隙，两个具有局部共振的重叠带隙主宰，还有两个聋人乐队。耦合模式导致耦合带隙的产生和波衰减的改善。实验和数值分析均表明，与具有单型孔的超材料相比，所提出的超材料可以在亚波长频域中创建多个带隙，其中包括具有降低的频率为76％的两个布拉格带隙，两个具有局部共振的重叠带隙主宰，还有两个聋人乐队。