二维蜂窝结构声子晶体的负折射成像研究材料物理与化学专业论文.docxVIP

广东工业大学硕士学位论文本文的最后给出论文研究总结。 广东工业大学硕士学位论文 本文的最后给出论文研究总结。 关键字：声子晶体；负折射效应；等频线；平板成像；分辨率 万方数据 ABSTRACTAB ABSTRACT AB STRACT Owning the elastic band gap，phononic crystal is a kind of periodic composite materials or structures．The phononic band gap is the most significant physical characteristics of phononic crystal．It means that when the frequency of elastic wave corresponds with that in the range of band gap，the wave will be stop to propagate in this phononic crystal．Because of the properties of phononic crystal，it Can be designed into many new acoustic devices and has a great application prospect in the field of noise reduction of vibration isolation．Atier 20 years of development，the studies on phononic crystal i s no longer confined to the band gap characteristics．It gradually tums to the part of pass band with the deeper understanding of phononic crystal．Some‘peculiar phenomena such as negative refraction，self-collimation， acoustic cloaking，which are in use of the passband performance of phononic crystal， have gain more and more attentions，and the potential applications such as flat lens and invisibility cloak，based on these phenomena，are even exciting．In this paper， negative refraction and imaging features of two—dimensional phononic crystal with honeycomb·lattice are studied by finite element method．The following is the content of the paper． In chapter one，the basic concept of phononic crystals is firstly introduced on the basis of the electronic band theory and the analogy of photonic crystal．Then we discourse its basic features，including the band gap and defect mode characteristics and negative refraction，etc．The research status and the main application of phononic crystal is given in the last． In chapter two，the fundamental theory and knowledges of negative refraction effect of phononic crystal given．Firstly we introduce the rise of left．handed materials，which is the origin of negative refraction phenomenon，and then we tell the general imaging laws and mechanism o