A novel auxetic acoustic metamaterial plate with enlarged bandgap

In the future, to meet the complex and changeable conditions of the actual environment, the development of multi-functional metamaterials that can realize the superposition of multiple properties is attractive. In this work, a novel acoustic metamaterial based on variable stiffness factor (VSF) perforated plates is proposed. Based on Bloch theorem, the dispersion curves of the proposed structures are calculated using finite element software, and the results are verified by calculating the transmission loss curves. The bandgap characteristics can be slightly improved by varying the VSF values. Compared with positive and negative Poisson's ratio metamaterials with the same porosity, the proposed structure can achieve lower frequency and wider bandgap. Secondly, the two typical acoustic metamaterials proposed in this paper have ultra-wide bandgap widths of 121 % and 112 % respectively. With the change of strain, the bandgap of the structure can be adjusted in real-time, which is valuable for the study of low-frequency bandgap. The new findings in this paper promote the development of columnar metamaterials and also provide a new idea for the study of multi-property superimposed metamaterials.