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兰姆波在声子晶体薄板中的传播特性因其在无损检测、减振技术和传感器件等领域的潜在应用价值而受到越来越多的关注.本文采用超原胞平面波展开法和有限元法系统地研究了复合对称结构声子晶体薄板中的兰姆波超宽部分禁带.结果表明:对于在薄板侧面对称地嵌入双层矩形空气柱构成的复杂系统,低阶兰姆波部分带隙结构极为丰富.将晶格常数(L)和板厚(H)比值具有匹配关系的兰姆波声子晶体衔接构成复合结构,低阶兰姆波部分禁带宽度因各组分结构的部分禁带交叠而得到显著拓宽,可在低频超宽频带内实现对特定低阶兰姆波模式良好的模式选择功能.该研究结果对兰姆波缺陷无损检测中模式优化选择及兰姆波单向导通器件设计等方面具有重要意义.
Due to its potential application value in non-destructive testing, vibration-damping technology and sensor devices, Lamb wave propagation characteristics in phononic crystal sheet are receiving more and more attention. In this paper, superplastic plane wave expansion method and finite element The results show that for the complex system composed of two layers of rectangular air column symmetrically embedded in the side of the thin plate, the low order Lamb wave partial band And the gap structure is very rich.When the Lamb wave phononic crystals with a matching lattice ratio (L) and plate thickness (H) ratio are connected to form a composite structure, the bandgap of the low-order Lamb wave part is changed due to the part of each component structure Band gap overlapped and broadened significantly to achieve a good mode selection function for a specific low-order Lamb wave mode in the low-frequency ultra-wideband.The results of this study on the choice of mode optimization and Lamb wave singlet in the non-destructive testing of Lamb wave To the conduction device design and so on is of great significance.