Jo Soo-Ho, Yoon Heonjun, Shin Yong Chang, Choi Wonjae, Youn Byeng D, Kim Miso
Department of Mechanical Engineering, Seoul National University, Seoul, 08826, Republic of Korea.
Institute of Advanced Machines and Design, Seoul National University, Seoul, 08826, Republic of Korea.
Nano Converg. 2022 Jun 15;9(1):29. doi: 10.1186/s40580-022-00321-x.
This study proposes a phononic crystal (PnC) with triple defects in an L-shape arrangement for broadband piezoelectric energy harvesting (PEH). The incorporation of defects in PnCs has attracted significant attention in PEH fields owing to properties such as energy localization and amplification near the defect. Several studies have been conducted to enhance output electric power of PnC-based PEH systems with single defects. However, it is susceptible to the limitations of narrow bandwidth. Recently, double-defect-incorporated systems have been proposed to widen the PEH bandwidth via defect-band splitting. Nevertheless, the PEH performance rapidly decreases in the frequency range between the split defect bands. The limitations of single- and double-defect-incorporated systems can be resolved by the incorporation of the proposed design concept, called the L-shape triple defects in a PnC. The isolated single defect at the top vertex of the letter 'L' compensates for the limitations of double-defect-incorporated systems, whereas the double defects at the bottom vertices compensate for the limitations of the single-defect-incorporated systems. Hence, the proposed design can effectively confine and harvest elastic-wave energy over broadband frequencies while enhancing the application of single and double defects. The effectiveness of the proposed design concept is numerically validated using the finite element method. In the case of a circular hole-type PnC, it is verified that the PnC with L-shape triple defects broadens the bandwidth, and improves the output voltage and electric power compared with those of single- and double-defect-incorporated systems. This study expands the design space of defect-incorporated PnCs and might shed light on other engineering applications of the frequency detector and elastic wave power transfer.
本研究提出了一种具有L形排列三重缺陷的声子晶体（PnC），用于宽带压电能量收集（PEH）。由于缺陷附近的能量局域化和放大等特性，在PnC中引入缺陷在PEH领域引起了广泛关注。已经开展了多项研究来提高基于单缺陷PnC的PEH系统的输出电功率。然而，它容易受到带宽窄的限制。最近，有人提出了双缺陷系统，通过缺陷带分裂来拓宽PEH带宽。然而，在分裂缺陷带之间的频率范围内，PEH性能会迅速下降。通过引入所提出的设计概念，即在PnC中采用L形三重缺陷，可以解决单缺陷和双缺陷系统的局限性。字母“L”顶部顶点处的孤立单缺陷弥补了双缺陷系统的局限性，而底部顶点处的双缺陷则弥补了单缺陷系统的局限性。因此，所提出的设计能够在宽带频率上有效地限制和收集弹性波能量，同时增强单缺陷和双缺陷的应用。使用有限元方法对所提出设计概念的有效性进行了数值验证。对于圆孔型PnC，验证了具有L形三重缺陷的PnC与单缺陷和双缺陷系统相比，拓宽了带宽，提高了输出电压和电功率。本研究扩展了含缺陷PnC的设计空间，并可能为频率探测器和弹性波功率传输的其他工程应用提供启示。
