三明治型声子晶体中Lamb波传播特性的研究(英文)  

Study on the band gap variation caused by constructed materials in a sandwich phononic crystal

作　　者：刘聪[1] 徐晓东[1] 王敬时[1] 刘晓峻[1] 

机构地区：[1]近代声学教育部重点实验室,南京大学声学研究所,南京210093

出　　处：《南京大学学报（自然科学版）》2012年第5期531-536,共6页Journal of Nanjing University（Natural Science）

基　　金：National Natural Science Foundation of China(11074126)

摘　　要：近年来,Lamb波在声子晶体板中的传播特性受到了研究者的广泛关注.在前人的研究基础上,本文利用传统的一维声子晶体板构建了三明治型声子晶体复合板模型,并运用有限元法研究了三明治型复合板的上下覆盖层对Lamb波禁带分布的影响.所谓三明治型声子晶体复合板即通过在传统一维声子晶体板的上下表面对称覆盖一定厚度的纯材料板得到.利用该模型,数值分析了不同三明治型复合板中Lamb波的传输谱,计算结果证明,当上下两覆盖层的材料为硬材料时,覆盖层对禁带分布的影响巨大,禁带随着覆盖层变厚迅速消失;另一方面,若上下两覆盖层为软材料构成时,可以发现一个新禁带的形成,并且随着覆盖层厚度增加逐渐趋于与原禁带合并.而对于覆盖层为中等硬度材料的情况,覆盖层对禁带分布的影响介于软材料和硬材料之间.研究结果表明:当声子晶体的结构保持不变时,该声子晶体的禁带分布可通过构建相应的三明治模型进行调节.The characteristics of Lamb waves in phononic crystal plate have been studied recently as the wide applications of Lamb waves and great popularity of phononic crystal.This study distinguishes the models proposed in the previous papers and focuses on the influences of the loading layers that have different hardness.A sandwich-structured model,which is composed by a one-dimensional phononic crystal and two kinds of pure materials designed as the base layer and the top layer,is proposed and used to investigate the influence on the band gap distribution of Lamb waves by the finite element method.Based on the theoretical model,the transmitted power spectra of sandwich structured plate are calculated.The result demonstrates that when the base layer and the top layer are of hard material,the effect caused by layers on band gaps is significant and the band gaps disappear rapidly with the increasing thickness of layers.On the other hand,if the base and top layers are constructed with soft material,a new band gap gradually appears with the increasing thickness of layers,and tends to combine with the original band gap.In addition,for the case of medium-hardness loading layers,the influence of the loading layers is between those of the two cases described above.Thus,these properties can be applied to design and adjust band gap distribution artificially.

关 键 词：声子晶体 带隙 LAMB波 有限元 

分 类 号：O422[理学—声学]