局域共振型声子晶体板缺陷态带隙及其俘能特性研究

设计了一种由圆柱形散射体嵌入环氧树脂基体而组成的周期阵列局域共振型声子晶体板结构, 分析了其平直带区域以及缺陷态的能量集中特性, 并研究了其振动能量采集特性. 首先基于超元胞法结合有限元方法分析了5 $\times$ 5完美声子晶体结构和缺陷态声子晶体结构的能带曲线和能量传输特性; 考虑点缺陷局域共振声子晶体结构的能量集中特性, 利用压电材料代替超元胞中某点的散射体材料引入点缺陷, 分析其振动能量采集特性, 结果表明单个5 $\times$ 5点缺陷超胞结构共振频带较窄; 为提升俘能效率, 提出两种由3个具有不同缺陷态数量和构型的5 $\times$ 5超元胞结构并联而成的5 $\times$ 15声子晶体板结构, 机电耦合特性分析结果表明: 所提出的局域共振型声子晶体板结构克服了单个点缺陷超胞结构缺陷模过少、共振频带过窄的局限性, 拓宽了俘能器的工作频带, 提高了输出电压; 此外, 引入不同的缺陷态数量和构型, 可以进一步拓宽俘能带宽, 实现更好的俘能效果. 

STUDY ON THE BANDGAPS OF DEFECT STATES AND APPLICATION OF ENERGY HARVESTING OF LOCAL RESONANT PHONONIC CRYSTAL PLATE

A local resonant phononic crystal plate, which is composed by quadrangular epoxy resin matrix embedded with cylindrical scatterers, is proposed to study the vibration energy harvesting performance. The bandgaps and energy concentration characteristics for the defect state structure are analyzed in detail. Firstly, the bandgap curve and energy transmission characteristics are analyzed for perfect and point defect phononic plate with 5 $\times$ 5 array structure based on supercell theory and finite element method. Considering the energy concentration characteristics of the point defect local resonance phononic crystal structure, piezoelectric material is used to replace the scatterer material of defect point, and the vibration energy characteristics are then analyzed. The results show that it has narrow resonance frequency band for the 5 $\times$ 5 point defect supercell structure. In order to improve the energy capture efficiency, two kind of new phononic crystal plate composed of three 5 $\times$ 5 supercells with different defect numbers and layout are proposed as the vibration energy harvester. According to the results of the electromechanical coupling analysis, it shows that the proposed local resonant phononic crystal plate overcomes the disadvantages of the single point defect supercell structure, such as too few defect modes and too narrow resonance frequency band. The working frequency band of the energy harvester is widened and the output voltage is increased. Additionally, it can further broaden the energy harvesting bandwidth and achieve better efficiency by introducing different number and configuration of defect states.