Collaborative Research: Cellular Metamaterials that Localize Stress - Towards a Topological Protection against Fracture

合作研究：局部化应力的细胞超材料——实现拓扑防断裂

基本信息

批准号：
2026794
负责人：
Xiaoming Mao
金额：
$ 23.89万
依托单位：
Regents of the University of Michigan - Ann Arbor
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-12-15 至 2024-11-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2026794&HistoricalAwards=false
关键词：
Collaborative Research Cellular Metamaterials Localize

项目摘要

One of the main challenges in designing engineering structures that can withstand severe loading conditions is the development of materials that can intelligently manage stresses to avoid or retard the onset and propagation of fracture. Most traditional approaches towards this goal involve improvements in the microstructural composition of the material to increase toughness. This award revisits fracture in the context of lattice materials featuring a cellular architecture, where protection can be sought not only by adjusting the material composition but also through changes in the morphology of the cellular structure. The focus will be on a special class of lattice materials in which it may be possible to concentrate the stresses due to external loading at known, desirable locations, providing the ability to prevent or delay the onset of damage processes. The knowledge gained from this research will contribute towards the longevity and reliability of structural systems across engineering applications, from infrastructural engineering to the aerospace industry. The project will also support design of innovative demonstration kits on stress analysis for undergraduate students and demonstrations of basic principles of structural analysis for high-school students and the public.The objective of this project is to investigate the potential of topology in cellular metamaterials in managing internal stresses and protecting against fracturing. The project is centered on Maxwell lattices that can contain topologically polarized states, including topologically protected states of self-stress along internal domain walls or interfaces. When these lattices are loaded and deformed, the stress tends to focus predominantly on these interfaces, even in the presence of cracks in the domain. As a result, the detrimental stress concentration and subsequent fracturing, which is typically observed at crack tips can be avoided or significantly retarded. The project will assess how this property, which depends on the bulk architecture of the lattice, is preserved in going from ideal lattices endowed with perfect hinges to realistic lattices featuring structural ligaments. This objective will be achieved through an experimental characterization based on digital image correlation accompanied by theoretical development that will extend the topological fracture protection to the continuum limit. Efforts will be also devoted to determining how deep into the topological protection the material itself is affected by failure, an assessment of which will be sought experimentally using acoustic emission monitoring.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.

设计可以承受严重加载条件的工程结构的主要挑战之一是材料的开发可以智能地管理压力，以避免或阻碍骨折的发作和传播。实现此目标的大多数传统方法都涉及改进材料的微结构组成，以提高韧性。该奖项在具有细胞结构的晶格材料的背景下重新审视了断裂，在该晶格材料中，不仅可以通过调整材料组成，而且可以通过改变细胞结构的形态来寻求保护。重点将放在一类特殊的晶格材料上，在这些晶格材料中，由于在已知的，理想的位置外部负载而引起的应力，从而提供了预防或延迟损害过程发作的能力。这项研究所获得的知识将有助于跨工程应用程序的结构系统的寿命和可靠性，从基础设施工程到航空航天行业。该项目还将在本科生的压力分析中支持设计创新的演示套件，并为高中生和公众提供结构分析的基本原理。该项目的目的是研究拓扑中拓扑的潜在，以管理内部压力和保护内部压力和保护破裂。该项目以麦克斯韦晶格为中心，麦克斯韦晶格可以包含拓扑两极化的状态，包括沿着内部域墙壁或接口的拓扑保护状态。当这些晶格被加载和变形时，即使在域中存在裂缝的情况下，应力也倾向于主要集中在这些界面上。结果，通常可以避免或显着阻碍裂纹尖端观察到的有害应力浓度和随后的压裂。该项目将评估该属性如何取决于晶格的庞大结构，从而从具有完美的铰链到具有结构韧带的逼真的晶格中保存下来。这一目标将通过基于数字图像相关性的实验表征来实现，并伴随着理论发展，这将扩展到连续限制的拓扑断裂保护。努力还将致力于确定材料本身受到失败影响的拓扑保护的深度，该评估将通过声学发射监控进行实验寻求。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的审查标准来通过评估来支持的。