缺陷态对4340钢-环氧树脂二维声子晶体带隙的影响

采用平面波展开法及平面波超元胞法研究缺陷态对4340钢-环氧树脂二维声子晶体带隙的影响. 以环氧树脂作为基底,把正方形结构排列的4340钢均匀的插入基底中,计算完整晶体、45°线缺陷态晶体、90°线缺陷态晶体、135°线缺陷态晶体、180°线缺陷态晶体的带隙. 结果表明,缺陷态的带隙宽度与完整晶体的带隙宽度相比最大可增大约31倍;对于不同的缺陷结构在F=0.1-0.9的范围内均有带隙出现且随着缺陷态角度的增大. 同时讨论带隙数目N,最低带隙相对宽度Δω/ω_g与填充率F之间的关系.关键词：缺陷态带隙宽度带隙数目

Influence of defect states on band gaps of the 4340 steel in epoxy in two-dimensional phononic crystal

The band gaps of a two-dimensional phononic crystal are studied by using the plane-wave expansion method and the supercell calculations. The two-dimensional phononic crystal is formed by square-shape arrangement of 4340 steel inserted into epoxy resin. The band gaps of different structures are calculated such as defect-free, 45° crystal defect states, 90° crystal defect states, 135° crystal defect states and 180° crystal defect states. It is found that the bandwidth of defect state is about 31 times larger than that of the defect-free crystal; with F=0.1—0.9 the band gaps occur in different defect structures and increase with defect state angle increasing. In addition, the influences of filling fraction on the band gap number and the relative width of the minimum band gap are also discussed.