Frustrated Metamaterials as Shape-Morphing Structures

作为形状变形结构的受挫超材料

• 批准号: 2045191
• 负责人: Paolo Celli
• 金额: $ 30.26万
• 依托单位: SUNY at Stony Brook
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-15 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2045191&HistoricalAwards=false
• 关键词: Frustrated; Metamaterials; Shape; Morphing; Structures

This grant will support research on the mechanics of frustrated mechanical metamaterials and will explore their applicability as large-scale structures. Metamaterials are assemblies of simple structural elements like beams and plates that, in concert, yield extreme shape transformations and other unconventional responses. Periodic metamaterials feature low-energy modes of deformation called mechanisms. In the presence of non-periodicity, mechanisms are impeded by incompatibilities between the deformations of neighboring units. These are usually seen as a nuisance; in this project, they are instead embraced to achieve functionality. Indeed, in two-dimensional systems, the geometric “frustration” stemming from incompatibilities results in out-of-plane buckling, and the initially flat system morphs (literally, pops-up) into a three-dimensional shell-like object. This research will create knowledge on the origin and manifestation of frustration in two-dimensional metamaterials and will explore their applicability as large-scale deployable structures with the following unique attributes: (i) they pop-up due to tensile (rather than compressive) forces; (ii) they can be prestressed without ground anchoring; (iii) they can be accurately deployed since the desired shape is encoded within the flat precursor. The ideas within this project have the potential to revolutionize how engineers think about designing deployable systems and erecting lightweight freeform structures like gridshells, large domes, and pop-up shelters. The educational activities, centered around the theme of shape morphing and based on both curriculum development and undergraduate student empowerment, will stimulate structural engineering students to embrace creativity and to revisit their preconceived idea of structures as non-changing, static entities. The primary objective of this project is to provide a systematic understanding of geometric frustration in various non-periodic metamaterial systems, and to exploit this knowledge to realize innovative shape-morphing structures. The first step will be to elucidate the in-plane prerequisites to frustration via theoretical, experimental, and numerical means. Attention will be devoted to the interplay between the location and magnitude of the actuation, the metamaterial’s architecture, and the location of the compressive regions prone to buckling. Reduced-order numerical models will be leveraged to predict out-of-plane shape transitions. Steps will also be taken to formulate a mechanistic inverse design, i.e., to find the in-plane architecture and the location and extent of the actuating forces necessary to obtain a target three-dimensional shape. Finally, the principles of frustration, initially studied via tabletop-scale prototypes, will be translated to large scales. The deployability and load bearing capacity of metamaterial-inspired frustrated structures will be investigated via experiments and numerical simulations. A new course on shape-shifting is planned. Both undergraduate and graduate students will be trained as the new generation of "structures thinkers."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.

这笔赠款将支持受挫机械超材料的力学研究，并将探索其作为大型结构的适用性。超材料是梁和板等简单结构元素的组合，它们共同产生极端的形状变换和其他非常规超材料。具有称为机制的低能量变形模式。在存在非周期性的情况下，机制会受到相邻单元变形之间的不兼容性的阻碍。事实上，在这个项目中，它们被用来实现功能。事实上，在二维系统中，由于不兼容性而产生的几何“挫败”会导致平面外屈曲，并且最初平坦的系统会变形（字面意思是弹出）。这项研究将创造关于二维超材料中挫败感的起源和表现的知识，并将探索它们作为具有以下独特属性的大规模可部署结构的适用性： (i) 它们由于拉伸（而不是压缩）力而弹出；(ii) 它们可以在没有地面锚固的情况下施加预应力；(iii) 由于所需的形状被编码在平坦的前体中，所以它们可以被精确地部署。该项目有可能彻底改变工程师对设计可部署系统和建造网格壳、大型圆顶和弹出式庇护所等轻型自由形状结构的思考方式。教育活动以形状变形为主题，并基于课程开发。和本科生赋权，将激发结构工程专业的学生拥抱创造力，并重新审视他们将结构视为不变的静态实体的先入为主的想法。该项目的主要目标是提供对各种非几何挫败感的系统理解。周期性超材料系统，并利用这些知识来实现​​创新的形状变形结构，第一步将是通过理论、实验和数值手段阐明平面内的先决条件。和幅度驱动、超材料的结构以及容易屈曲的压缩区域的位置也将被用来预测面外形状转变，即：找到获得目标三维形状所需的平面内架构以及驱动力的位置和范围。最后，最初通过桌面规模原型研究的挫败原理将转化为大型模型。计划通过实验和数值模拟来研究受超材料启发的受挫结构的可部署性和承载能力，计划将本科生和研究生培养为新一代的“结构思想家”。 ” “该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Modelling planar kirigami metamaterials as generalized elastic continua

将平面剪纸超材料建模为广义弹性连续体

• DOI: 10.1098/rspa.2022.0665
• 发表时间: 2022-05-31
• 期刊: Proceedings of the Royal Society A
• 作者: Yue Zheng;Ian Tobasco;P. Celli;Paul Plucinsky
• 通讯作者: Paul Plucinsky