Natural Curvature and Soft Shells: Shape Shifting through Mechanical Instabilities

自然曲率和软壳：通过机械不稳定性改变形状

• 批准号: 1824882
• 负责人: Douglas Holmes
• 金额: $ 53.15万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-15 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1824882&HistoricalAwards=false
• 关键词: Natural; Curvature; Soft; Shells; Shape

Nature uses internal stimuli to locally and globally change the curvature of thin and soft materials in a variety of ways. Natural curvatures occur in many biological and engineered structures through differential swelling, heating, or growth. They are: induced by proteins along a cell membrane, critical to the eversion of a developing Volvox embryo, and incurred in residually stressed composite plates and shells. Since natural curvature can drastically affect the morphology of thin bodies and induce mechanical instabilities, this provides a means for creating adaptive, shape-shifting structures capable of growing, morphing, and transitioning between complex shapes. This award supports fundamental research on the mechanics of instabilities induced by a natural curvature within thin shells. Harnessing these concepts for technological applications may enable the design of adaptive metamaterials, soft robotic actuators, and structural materials capable of programmatically controlled shape-shifting. Thus, this project will advance the science associated with mechanical instability; and advance the national health, prosperity, and welfare. This award also supports the further development of the digital inspiration, communication, and education (DICE) program. By placing an emphasis on visual, verbal, and written communication, this program will continue to enhance both the scientific communication of the next generation of scholars and broaden the participation of the general public through the creation and curation of open, online mechanics content.This research will establish a fundamental understanding of how natural and spontaneous curvatures deform slender structures and soft materials. Its results will help engineer shells that are more robust against buckling, and facilitate the design of shells capable of changing between target shapes on command. The research will establish how natural curvature can provide shells with a knock-up factor against pressure buckling. The research team will utilize experiments that control curvature in soft materials through residual swelling in conjunction with a novel computational model based on a large deformation, rotation-free shell formulation. A fully nonlinear forward and inverse computational shell model to analyze shells with an evolving natural curvature will be developed and validated with experiments. Finally, an understanding of how locally applied natural curvatures deform soft shells will be established, enabling targeted shape-shifting that utilizes the computational modeling to inform the experimental design. This understanding may transform key technologies where shape-shifting materials are being intensely pursued for technological insertion, like soft robotics, deployable structures, and biomimetic design.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.

大自然利用内部刺激以各种方式改变局部和全球曲线。自然曲率通过差异，加热或生长发生在许多生物和工程结构中。它们是：沿细胞膜诱导的蛋白质，对发育中的Volvox胚胎的持久至关重要，并在残留的应力复合板和壳中产生。由于自然曲率可以严重影响薄体​​的形态并诱导机械不稳定性，因此这提供了一种能够在复杂形状之间生长，变形和过渡的自适应，形状变形结构的手段。该奖项支持对薄壳内自然曲率引起的不稳定性机制的基本研究。利用这些概念用于技术应用，可以使自适应超材料，软机器人执行器和能够编程控制形状转移的结构材料的设计。因此，该项目将推动与机械不稳定性相关的科学。并促进民族健康，繁荣和福利。该奖项还支持数字灵感，沟通和教育（DICE）计划的进一步发展。通过强调视觉，言语和书面交流，该计划将继续增强下一代学者的科学交流，并通过开放的在线力学内容的创建和策划来扩大公众的参与。这项研究将建立对自然和自发的弯曲曲线的基本了解。它的结果将有助于工程贝壳，这些外壳能够防止屈曲，并有助于设计能够在指挥部目标形状之间变化的壳的设计。这项研究将确定自然曲率如何为壳体提供针对压力屈曲的敲击因子。研究团队将利用基于较大变形，无旋转的壳体配方的新型计算模型，通过残留的肿胀来控制软材料中的曲率。将通过实验开发和验证一个完全非线性的前进和逆计算壳模型，用于分析具有不断发展的自然曲率的壳。最后，了解将如何建立局部应用的自然曲率变形软壳，从而实现了靶向形状转换，从而利用计算建模来为实验设计提供信息。这种理解可能会改变关键技术，其中正在为技术插入而强烈追求形状变形材料，例如软机器人技术，可部署的结构和仿生设计。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的影响审查标准来通过评估来通过评估来支持的。

项目成果

Buckling of geometrically confined shells

• DOI: 10.1039/c8sm02035c
• 发表时间: 2019-02-14
• 期刊: SOFT MATTER
• 影响因子: 3.4
• 作者: Stein-Montalvo, Lucia;Costa, Paul;Holmes, Douglas P.
• 通讯作者: Holmes, Douglas P.

Grasping with kirigami shells

• DOI: 10.1126/scirobotics.abd6426
• 发表时间: 2021-05-12
• 期刊: SCIENCE ROBOTICS
• 影响因子: 25
• 作者: Yang, Yi;Vella, Katherine;Holmes, Douglas P.
• 通讯作者: Holmes, Douglas P.

Elastic Instabilities Govern the Morphogenesis of the Optic Cup

• DOI: 10.1103/physrevlett.127.138102
• 发表时间: 2021-09-23
• 期刊: PHYSICAL REVIEW LETTERS
• 影响因子: 8.6
• 作者: Lee, Jeong-Ho;Park, Harold S.;Holmes, Douglas P.
• 通讯作者: Holmes, Douglas P.

Efficient snap-through of spherical caps by applying a localized curvature stimulus

• DOI: 10.1140/epje/s10189-021-00156-0
• 发表时间: 2021-08
• 期刊: The European Physical Journal E
• 作者: Lucia Stein-Montalvo;Jeong-Ho Lee;Yi Yang;Melanie Landesberg;Harold S. Park;D. Holmes

Delayed buckling of spherical shells due to viscoelastic knockdown of the critical load

由于临界载荷的粘弹性降低导致球壳延迟屈曲

• DOI: 10.1098/rspa.2021.0253
• 发表时间: 2021
• 期刊: Physical and Engineering Sciences
• 作者: Stein-Montalvo, Lucia;Holmes, Douglas P.;Coupier, Gwennou
• 通讯作者: Coupier, Gwennou