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

这个早期概念探索性研究奖助金(EIGER)项目涉及一种古老而普遍但未被研究的材料类别：针织面料。其目的是利用理论物理中最新发展的概念和基础实验来探索这些新材料及其不同寻常的弹性性质，为这一研究领域的发展奠定坚实的基础。几千年来，工程师和工匠已经开发出了将纱线编织成具有所需性能的织物的方法，现在出现了许多新的应用，如软致动器、动画玩具、人造肌肉、改善道路和武器保护等。尽管针织面料有着广泛的用途，但它们的本质仍然是基本的和基础性的问题--它们的结构是如何产生其不同寻常的弹性性能的。回答这个问题可以让我们设计出比现有材料更坚固、更坚固的新面料。此外，它还可以让我们设计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广泛联系广大公众与科学和工程的完美工具，因为有许多工匠和业余爱好者从事针织材料的工作。为此，该项目包括面向学龄儿童和针织爱好社区的外展活动。该项目的目标是利用凝聚态物理学的新方法和新想法，建立对针织面料中异常弹性现象的理论力学理解。利用这些方法，这项工作还试图打开这些材料中受拓扑保护的振动边缘模式的领域，并在设计中实验观察这些模式，这些模式将在理论上得到识别。该方法将侧重于将纽结理论和凝聚物群理论应用于周期和准周期结构(包括缺陷系统)，以解释在实验中看到的奇怪的弹性性质，并解释这些系统中尽管由高刚性纱线组成的高弹性。在这方面，这项工作还将检验手性和群论在解释实验中看到的行为方面的作用。类似于凝聚态物理中的安德森局域化，该方法还将探索无序导致振动局部化的可能性，以及设计的无序是否可以导致强度增强。所获得的理论理解和实验演示旨在为新的和有前景的应用奠定基础。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.