EAGER: Knit One, Purl Two, Studies on the Properties of Knitted Fabrics for Advanced Engineering Applications

这个探索性研究的早期概念资助（EAGER）项目关注的是一种古老的、无处不在的、但尚未被充分研究的材料：针织织物。目的是探索这些新材料及其不同寻常的弹性特性，利用理论物理学中最新发展的概念和基础实验，为这一研究领域的发展奠定坚实的基础。几千年来，工程师和工匠们已经开发出了将纱线织成具有所需性能的织物的方法，如今，许多新的应用正在出现，例如软驱动器、动画玩具、人造肌肉、改善的道路和武器保护，等等。尽管针织织物的用途广泛，但关于其真正性质的基本和基础问题仍然存在-它们的结构如何产生其不同寻常的弹性性能。回答这个问题可以让我们设计出比现有材料更坚固、更坚固的新织物。此外，它可以让我们设计出以定向和可预测的方式传输能量的织物，用于执行器和能量耗散系统。针织面料的研究也是一个完美的工具，广泛地将更广泛的公众与科学和工程联系起来，因为有许多工匠和业余爱好者使用针织材料。为此，该项目包括向在校儿童和编织爱好社区开展外展活动。该项目的目标是利用凝聚态物理的新方法和思想，建立基于理论力学的针织物异常弹性现象的理解。使用这些方法，本工作还试图打开这些材料中拓扑保护振动边缘模式的领域，并在理论上确定的设计中实验观察这些模式。该方法将侧重于将结理论和凝聚态群理论应用于周期和准周期结构（包括缺陷系统），以解释实验中看到的奇怪弹性特性，并解释尽管由高刚性纱线组成，但在这些系统中看到的高弹性。在这方面，我们还将研究手性和群论在解释实验观察到的行为中的作用。类似于凝聚态物理中的安德森局域化，该方法还将探索织物中的无序导致振动局域化的可能性，以及设计的无序是否会导致强度增强。所获得的理论认识和实验演示旨在为新的和有前途的应用奠定基础。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 EArly-Concept Grants for Exploratory Research (EAGER) project concerns the study of an ancient and ubiquitous, yet understudied, class of materials: knitted fabrics. The aim is to explore these novel materials, and their unusual elastic properties, using recently developed concepts in theoretical physics together with basic experiments for the establishment of a firm foundation upon which this field of study can grow. Engineers and artisans have developed for millennia methods for weaving yarns into fabrics with desired properties, and nowadays many novel applications are appearing, such as soft actuators, animated toys, artificial muscles, improved roadways, and armament protection, to name a few. Despite the wide range of uses of knitted fabrics, basic and foundational questions remain about their true nature – how their structures give rise to their unusual elastic properties. Answering this question can allow us to design new fabrics that are stronger and more robust than existing materials. Further, it can allow us to design fabrics that transport energy in directed and predictable ways for use in actuators and energy dissipation systems. The study of knitted fabrics is also a perfect vehicle for broadly connecting the wider public with science and engineering as there are many artisans and hobbyists working with knitted materials. To that end the project includes outreach activities to school children and knitting hobby communities.The objective of this project is to establish a theoretical mechanics-based understanding of anomalous elastic phenomena in knitted fabrics using novel methods and ideas from condensed matter physics. Using these approaches, this work also seeks to open the field of topologically protected vibrational edge modes in these materials and to experimentally observe these modes in designs that would be identified theoretically. The approach will focus on the application of knot theory and condensed matter group theory applied to periodic and quasi-periodic structures (including defected systems) to explain the odd elastic properties seen in experiments and to explain the high elasticity seen in these systems despite being composed of high rigidity yarns. In this regard, the effort will also examine the role of chirality and group theory in explaining experimentally seen behaviors. Analogous to Anderson localization in condensed matter physics, the approach will also explore the possibility that disorder in fabrics leads to localization of vibrations, and whether designed disorder can lead to strength enhancements. The gained theoretical understanding and experimental demonstrations are intended to lay the foundation for new and promising applications.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.