带点缺陷的一维亥姆霍兹共振腔声子晶体中缺陷模式

在基于亥姆霍兹共振腔的一维声子晶体中引入点缺陷会在原有局域共振型声禁带内产生缺陷模式。采用传递矩阵法和有限元法分析了缺陷模式随缺陷单元几何尺寸变化关系和声子晶体中声场分布情况。结果表明,随着缺陷单元与完美单元之间耦合程度的增强,缺陷模式从局域共振型禁带中完美单元共振频率处向禁带边缘移动。同时,缺陷模式的存在使得结构中出现了能量局域化的现象。本工作对设计新型声滤波器、能量集中装置具有一定的理论意义。

Defect modes in the phononic crystal based on Helmholtz resonators with point defect

Defect mode can be created by introducing point defect in the one-dimensional crystal containing Helmholtz resonators. Based on acoustic transfer matrix method and finite element method, the relationship between the defect mode and the geometrical parameters of the defect cell is studied as well as the acoustic field distribution in the structure at the frequency of the defect mode. The results show that the defect mode moves to the edges of the local resonant forbidden band with the increase of the coupling effect between the defect cell and the perfect cells. In addition, acoustic energy localization is also observed due to the existence of the defect state. This work will be of help for designing new acoustic filters and energy concentrators.