Collaborative Research: Tailoring Energy Landscapes to Harness the Multistability for Reconfigurable 3D Buckled Structures

该基金将专注于三维（3D）结构的多稳定性基础研究，以实现良好控制、主动的建筑可重构性。可重构结构可以主动改变其几何形状，从而在外部刺激（如机械力、磁场、电场、水合作用、温度和压力）下改变其功能。这种智能、刺激响应结构在可展开的太阳能电池板、电磁超材料、光子学、生物医学设备、软机器人、超表面等领域有着广泛的应用。然而，大多数现有的重构机制需要持续的外部刺激来维持变形的形状。利用结构不稳定性的可重构性已经成为设计各种多功能可重构设备的一种流行而有力的手段，这些设备可以在不需要持续外部刺激的情况下保持其变形形状。尽管进行了深入的研究，但难以实现良好控制的建筑可重构性严重阻碍了可重构结构的合理设计，特别是对于由薄膜组成的结构。本研究项目将重点了解三维薄膜结构的几何和力学性能与其多稳定性之间的基本关系，并确定从一种稳定状态到另一种稳定状态的节能重构路径。除了研究活动外，该项目还将通过支持跨学科博士生培训、本科生研究机会以及向代表性不足群体的6-9年级女孩和K-5年级学生提供外展活动，为研究生、本科生和K-12年级学生的教育做出贡献。该项目的目标是揭示控制柔性三维（3D）薄膜结构的多稳态、对称和非对称配置的建筑重构的基本力学。为了实现这一目标，本项目的具体目标包括：(1)通过能量景观偏置最大化三维薄膜结构稳定状态之间的能量势垒并消除中间局部最小值；(2)最小化从一个局部最小值状态到另一个局部最小值状态的形状变化的能量成本，并通过磁力控制实现三维薄膜结构的可重构性。研究成果将通过(i)建立薄膜结构的几何形状和材料组成与不同稳定状态的能量景观之间的关系，以及（ii）确定有效地将结构从一个稳定状态操纵到另一个稳定状态的主动力，从而显著提高我们在多稳定结构力学方面的知识。此外，该项目最终将促进良好控制、智能可重构结构的设计，并对其他领域产生广泛影响，包括物理、材料科学、智能材料和结构。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 grant will focus on fundamental studies on the multistability of three-dimensional (3D) structures for well-controlled, active architectural reconfigurability. Reconfigurable structures can actively change their geometries and thereby their functionalities upon external stimuli (like mechanical forces, magnetic fields, electric fields, hydration, temperature, and pressure). Such smart, stimuli-responsive structures have a diverse range of applications in deployable solar panels, electromagnetic metamaterials, photonics, biomedical devices, soft robotics, metasurfaces, and many others. Most existing reconfiguration mechanisms, however, require persistent external stimuli to maintain the deformed shape. Reconfigurability through harnessing structural instabilities has emerged as a popular and powerful means of designing various multifunctional reconfigurable devices that can maintain their deformed shape without the need for persistent external stimuli. Despite intensive studies, the difficulty in realizing well-controlled architectural reconfigurability has significantly hindered the rational design of reconfigurable structures, especially for those composed of thin films. This research project will focus on understanding the fundamental relationship between the geometry and mechanical properties of 3D thin-film structures and their multistability and identifying the energy-efficient reconfiguration path from one stable state to another. In addition to the research activities, the project will contribute to the education of students at the graduate, undergraduate, and K-12 levels by supporting interdisciplinary doctoral student training, undergraduate research opportunities, and outreach activities to grade 6-9 girls and K-5 students from underrepresented groups.The objective of this project is to unravel the fundamental mechanics that govern architectural reconfiguration among multistable, symmetric and asymmetric configurations of flexible, three-dimensional (3D) thin-film structures. To achieve this objective, the specific aims of this project include: (1) maximize the energy barrier and eliminate intermediate local minima between stable states of 3D thin-film structures through energy landscape biasing, and (2) minimize the energy cost for shape change from one local minimum state to another, and realize the reconfigurability of 3D thin-film structures through magnetic force control. The research outcomes of the work will significantly advance our knowledge in the mechanics of multistable structures by (i) establishing relations between geometries and material compositions of thin-film structures and the energy landscape of different stable states, and (ii) determining the active forces to efficiently maneuver the structure from one stable state to another following the minimum energy path. In addition, the project will ultimately facilitate the design of well-controlled, smart reconfigurable structures and generate broad impacts on other fields, including physics, materials science, and smart materials and structures.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.