Elastic wave and vibration bandgaps in two-dimensional acoustic metamaterials with resonators and disorders
Elastic wave and vibration bandgaps in two-dimensional acoustic metamaterials with resonators and disorders
复制标题
具有谐振器和紊乱的二维声学超材料中的弹性波和振动带隙
DOI：
10.1016/j.wavemoti.2018.04.002
复制
发表时间：
2018-07-01
期刊：
影响因子：
2.4
通讯作者：
Zhang, Chuanzeng
中科院分区：
文献类型：
--
作者：
An, Xiyue;Fan, Hualin;Zhang, Chuanzeng
研究了由离散质量块和弹簧组成的二维有限长声学超材料的振动特性。为了阐明AM中带隙的形成机理，本文还研究了无限对称系统，特别是连接单元格的弹簧刚度系数不一致引起的物理不对称性的影响。虽然不对称性不能改变带隙宽度，但相速度的变化和剪切模式的产生已被解析地证明。为了研究有限AM模型的振动特性，使用每个单元的有效质量。讨论了二维AM中单谐振腔和多谐振腔时谐激励下单胞的有效质量特性。通过频率响应分析，研究了有限调幅模型中单元数目、单元内多谐振器数目、渐变谐振器数目对振动抑制效果的影响。数值计算结果表明，振动衰减的程度与模型的大小有关，带隙的数目随着局域谐振器的无序而变化。此外，缺陷或缺陷被引入到有限AM系统中。本文研究和讨论了直波导有限模型中波的传播和导行。证明了改变超原胞中心谐振腔的结构可以引入缺陷态。得到缺陷带，并说明它们的位置。(C)2018爱思唯尔B.V.保留所有权利。
The vibration properties of two-dimensional (2D) finite acoustic metamaterials (AMs) consisting of discrete masses and springs are investigated in this paper. In order to clarify the mechanisms of the bandgaps in AMs, the infinite symmetrical systems are also studied, especially the impact of the physical asymmetry caused by the discrepant stiffness coefficients of the springs connecting the unit-cells. Although the asymmetry cannot change the bandgap width, the change of the phase velocity and the generation of the shear mode have been proven analytically. To study the vibration properties of the finite AM model, the effective mass of each unit-cell is used. The effective mass properties of the unit cell with single resonator and multi-resonators in 2D AMs subjected to a time-harmonic excitation are discussed. The effects of the number of the unit-cells, multi-resonators in each unit-cell, graded resonators in the finite AM model on the vibration suppression are thoroughly examined by the frequency response analysis. Numerical results show that the degree of the vibration attenuation is related to the size of the model and the number of the bandgaps changes corresponding to the disorders of the local resonators. Furthermore, imperfections or defects are introduced into the finite AM system. Wave propagation and guiding in a finite model for straight waveguide are investigated and discussed. The defect states induced by changing the central resonator of a supercell are demonstrated. Defect bands are obtained and their location is illustrated. (C) 2018 Elsevier B.V. All rights reserved.