Vibration characteristics of innovative reentrant-chiral elastic metamaterials
Vibration characteristics of innovative reentrant-chiral elastic metamaterials
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DOI：
10.1016/j.euromechsol.2021.104350
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发表时间：
2021-06-24
影响因子：
4.1
通讯作者：
Yan, Gengwang
中科院分区：
文献类型：
--
作者：
Li, Yingli;Yan, Gengwang
在这项工作中，提出了一种创新的二维（2D）混合拉胀弹性超材料（模型I）与凹入三角形和手性结构，以打开加宽的带隙振动衰减。此外，嵌入谐振器的混合重入手征晶格（模型II）在超低频下显示出多个带隙。基于理论质量集中法和有限元法，对带隙和纵向弹性波衰减进行了表征。在经典的凹三角晶格（MODEL 0）中不存在完全带隙，而MODEL I和II的完全带隙宽度占相关频率范围（0-4500 Hz）的四分之一。此外，模型II的第一带隙的下限比模型I的第一带隙的下限低56%。通过分析色散曲线上的模式形状研究了带隙的形成机制，并通过等频线、相速度和群速度研究了与频率相关的能量流。最后，模型II的有限尺寸晶格的纵向弹性波衰减说明了超宽的振动衰减频率范围内的方向带隙。该研究为隔振器、梁、板等更新装置的设计提供了重要线索和理论指导。
In this work, an innovative two-dimensional (2D) hybrid auxetic elastic metamaterial (MODEL I) with reentrant triangular and chiral structures is proposed to open the broaden bandgap for vibration attenuation. Furthermore, the hybrid reentrant-chiral lattice with embedded resonators (MODEL II) shows multiple bandgaps at ultra-low frequency. Based on theoretical lumped mass-in-mass method and finite element method, the bandgap and longitudinal elastic wave attenuation are characterized. There is no complete bandgap in classical reentrant triangular lattice (MODEL 0), while the complete bandgaps width for MODEL I and II account for one forth of the concerned frequency range (0-4500 Hz). What more, the lower boundary of the first bandgap for MODEL II is 56% lower than that of MODEL I. The bandgap formation mechanisms are investigated by analyzing the mode shapes on the dispersion curves, and the frequency-dependent energy flow are studied through the iso-frequency contours, phase and group velocities. Finally, the longitudinal elastic wave attenuation of finite-size lattice of MODEL II illustrates ultra-wide vibration attenuation frequency range in the directional bandgaps. This research provides important clues and theoretical guidance for the design of vibration isolators, beam, plates and other renewed devices.