Towards Mechanical Resonators With Zero Leakage Using Elastic Metastructures

这笔拨款将支持产生与机械谐振器相关的新知识的研究，促进技术前沿和促进国家繁荣。机械振动器的例子包括通信装置、隔振器和能量收集装置。现有的谐振器由于能量泄漏到周围结构而受到固有的限制，并且根据需要提供有限或没有释放能量的手段。本研究将介绍和研究一类人工工程结构，称为元结构，可以实现零能量泄漏。它还将研究通过施加一个力来限制和释放能量的可能性。这些新型的机械谐振器将为弹性波计算和信号处理开辟新的途径，在机器人和物联网设备中具有潜在的应用前景。因此，这项研究的结果将有利于美国的经济和社会。此外，伴随的教育和推广活动将有助于扩大代表性不足的群体参与研究，并对工程教育产生积极影响。本研究将探讨实现零泄漏、缺陷不敏感、可以使用元结构按需限制和释放能量的机械谐振器的可能性。目前的设计存在这样一个问题，即它们会将能量泄漏到周围的结构中，并且无法根据需要释放能量。该研究将通过从波物理学的两个最新进展中获得灵感来克服这些限制：连续介质中的电磁束缚模式（bic）的演示和拓扑保护弹性波，使缺陷不敏感的能量传输成为可能。它将测试这样一个假设，即利用色散表面的对称性和拓扑结构可以在弹性介质中产生拓扑保护的bic。本研究将采用基于平面波展开法的解析计算、基于有限元分析的数值模拟和利用激光多普勒振动仪对预制样品进行实验测量相结合的方法来测量位移场。越来越复杂的元结构，即梁，板，壳和三维建筑固体，将被介绍和研究。这项研究的结果适用于广泛的长度尺度，并将跨学科转化为声学、电磁和等离子体元结构。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This grant will support research to generate new knowledge related to mechanical resonators, promoting the frontiers of technology and advancing national prosperity. Examples of mechanical vibrators include communication devices, vibration isolators and energy harvesting devices. Existing resonators suffer from intrinsic limitations due to leakage of energy into the surrounding structure and offer limited or no means to release energy on demand. This research will introduce and investigate a class of artificially engineered structures, known as metastructures, that can achieve zero energy leakage. It will also investigate the possibility of confining and releasing energy by applying a force. These novel mechanical resonantors will open new avenues for elastic wave-based computation and signal processing, with potential applications in robotics and Internet of Things devices. Therefore, results from this research will benefit the U.S. economy and society. Furthermore, the accompanying educational and outreach activities will help broaden participation of underrepresented groups in research and positively impact engineering education.This research will investigate the possibility of achieving mechanical resonators that have zero leakage, are defect-insensitive and can confine and release energy on demand using metastructures. Current designs suffer from the fact that they leak energy into the surrounding structure and are unable to release energy on demand. The research will overcome these limitations by drawing inspiration from two recent advances in wave physics: the demonstration of electromagnetic bound modes in the continuum (BICs) and topologically protected elastic waves that enable defect-insensitive energy transport. It will test the hypothesis that exploiting the symmetry and topology of the dispersion surfaces can lead to topologically protected BICs in elastic media. The research will use a combination of analytical calculations based on the plane wave expansion method, numerical simulations using finite element analyses and experimental measurements on fabricated samples by using laser Doppler vibrometry to measure the displacement field. Metastructures of increasing complexity, i.e., beams, plates, shells and three-dimensional architected solids, will be introduced and investigated. The results of this research are applicable across a wide spectrum of length scales and will translate across disciplines to acoustic, electromagnetic and plasmonic metastructures.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.