CAREER: Guiding and Confining Nonlinear Elastic Waves in Moiré Metastructures

职业：在莫尔超结构中引导和限制非线性弹性波

• 批准号: 2238072
• 负责人: Raj Kumar Pal
• 金额: $ 50.43万
• 依托单位: Kansas State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2028-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2238072&HistoricalAwards=false
• 关键词: CAREER; Guiding; Confining; Nonlinear; Elastic

This Faculty Early Career Development (CAREER) grant will fund research that enables the application of new architected metamaterials to vibration protection of large-capacity wind turbine blades, as well as the design of surface acoustic wave devices capable of high-precision sensing and signal processing, thereby promoting the progress of science and advancing the national prosperity. A major impediment to scaling up the output from wind energy generation is structural failure due to vibrations of turbine blades induced by unsteady wind loads and extreme weather conditions. Without effective means to guide or isolate vibrational energy in such structures, concerns about damage and safety enforce suboptimal designs and operation. To address this challenge, this project investigates a hitherto unexplored class of engineered materials, called moiré metastructures, that can guide and confine elastic wave energy in ways that are unattainable in conventional materials. An integrated set of education and outreach activities aims to positively impact engineering education and contribute to a diverse and globally competitive STEM workforce. These include metastructure design challenges in an undergraduate course, hands-on activities at workshops for K-12 students, international student exchange with a research group in France, and participation of individuals from underrepresented groups in research.This research aims to develop the foundations for the design of a class of bilayered architected plate metastructures, coupled by nonlinear between-layer springs, that allow independent engineering of dispersion and nonlinearity and, as a result, the possibility of uniquely nonlinear wave phenomena, such as solitons, frequency combs, wave bending, and unidirectional propagation. It achieves this aim by investigating how nontrivial topological properties of moiré metastructures, obtained by stacking two layers of hexagonal, square, and Kagome lattice-based plates, result in almost flat dispersion bands that can be exploited and combined with space-time modulation of stiffness to guide or confine wave energy. The approach relies on theoretical analysis of discrete spring-mass models, finite-element analysis using discontinuous Galerkin basis functions based on Bloch modes, design optimization and fabrication of coupling springs with the desired nonlinear stiffness, and experimental validation using laser-Doppler vibrometry and high-speed imaging.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.

该学院早期职业发展（CAREER）拨款将资助研究，使新型超材料应用于大容量风力涡轮机叶片的振动保护，以及能够高精度传感和信号处理的表面声波器件的设计，从而促进科学进步和促进国家繁荣，扩大风能发电的主要障碍是由于不稳定的风荷载和极端天气条件引起的涡轮叶片的振动而导致的结构故障。为了解决这一挑战，该项目研究了一种迄今为止尚未开发的工程材料，称为莫尔超结构，它可以通过以下方式引导和限制弹性波能量。一套综合的教育和推广活动旨在对工程教育产生积极影响，并为培养多元化和具有全球竞争力的 STEM 劳动力做出贡献，其中包括本科课程中的元结构设计挑战、研讨会上的实践活动。 K-12 学生、国际学生与法国研究小组的交流以及来自代表性不足群体的个人参与研究。本研究旨在为设计一类双层建筑板元结构（通过非线性层间耦合）奠定基础。弹簧，允许色散和非线性的独立工程，因此，独特的非线性波现象的可能性，例如孤子、频率梳、波弯曲和单向传播。通过研究通过堆叠两层六角形、方形和 Kagome 晶格板获得的莫尔超结构的非平凡拓扑特性如何产生几乎平坦的色散带，可以利用该色散带并将其与刚度的时空调制相结合来引导该方法依赖于离散弹簧质量模型的理论分析、基于布洛赫模式的不连续伽辽金基函数的有限元分析、设计优化和制造具有所需非线性刚度的耦合弹簧，并使用激光多普勒振动测量和高速成像进行实验验证。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。