This study aims to investigate elastic wave localization that leverages defect band splitting in a phononic crystal with double defects through in-depth analysis of comparison of numerical and experimental results. When more than one defect is created inside a phononic crystal, these defects can interact with each other, resulting in a distinctive physical phenomenon from a single defect case: defect band splitting. For a phononic crystal consisting of circular-hole type unit cells in a thin aluminum plate, under A0 (the lowest antisymmetric) Lamb waves, both numerical simulations and experiments successfully confirm the defect band splitting phenomenon via frequency response functions for the out-of-plane displacement calculated/measured at the double defects within a finite distance. Furthermore, experimental visualization of in-phase and out-of-phase defect mode shapes at each frequency of the split defect bands is achieved and found to be in excellent agreement with the simulated results. Different inter-distance combinations of the double defects reveal that the degree of the defect band splitting decreases with the increasing distance due to weaker coupling between the defects. This work may shed light on engineering applications of a multiple-defect-introduced phononic crystal, including broadband energy harvesting, frequency detectors, and elastic wireless power transfer.

中文翻译：

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声子晶体中双缺陷诱导的弹性波耦合和能量定位

本研究旨在通过深入分析数值和实验结果的比较，研究利用双缺陷声子晶体中缺陷带分裂的弹性波定位。当声子晶体内产生多个缺陷时，这些缺陷会相互作用，从而导致单一缺陷情况下的独特物理现象：缺陷带分裂。对于由薄铝板中的圆孔型晶胞组成的声子晶体，在 A0（最低反对称）兰姆波下，数值模拟和实验均通过频率响应函数成功地证实了缺陷带分裂现象。在有限距离内的双缺陷处计算/测量的平面位移。此外，实现了分裂缺陷带每个频率下同相和异相缺陷模式形状的实验可视化，并发现与模拟结果非常吻合。双缺陷的不同间距组合表明，由于缺陷之间的耦合较弱，缺陷带分裂的程度随着距离的增加而减小。这项工作可能会阐明引入多缺陷的声子晶体的工程应用，包括宽带能量收集、频率检测器和弹性无线电力传输。双缺陷的不同间距组合表明，由于缺陷之间的耦合较弱，缺陷带分裂的程度随着距离的增加而减小。这项工作可能会阐明引入多缺陷的声子晶体的工程应用，包括宽带能量收集、频率检测器和弹性无线电力传输。双缺陷的不同间距组合表明，由于缺陷之间的耦合较弱，缺陷带分裂的程度随着距离的增加而减小。这项工作可能会阐明引入多缺陷的声子晶体的工程应用，包括宽带能量收集、频率检测器和弹性无线电力传输。