Lee Ting-Uei, Lu Hongjia, Ma Jiaming, Ha Ngoc San, Gattas Joseph M, Xie Yi Min
Centre for Innovative Structures and Materials, School of Engineering, RMIT University, Melbourne, VIC 3001, Australia.
School of Civil Engineering, University of Queensland, St. Lucia, QLD 4072, Australia.
Proc Natl Acad Sci U S A. 2024 Oct;121(40):e2409062121. doi: 10.1073/pnas.2409062121. Epub 2024 Sep 27.
Deployable tubular structures, designed for functional expansion, serve a wide range of applications, from flexible pipes to stiff structural elements. These structures, which transform from compact states, are crucial for creating adaptive solutions across engineering and scientific fields. A significant barrier to advancing their performance is balancing expandability with stiffness. Using compliant materials, these structures achieve more flexible transformations than those possible with rigid mechanisms. However, they typically exhibit reduced stiffness when subjected to external pressures (e.g., tube wall loading). Here, we utilize origami-inspired techniques and internal stiffeners to meet conflicting performance requirements. A self-locking mechanism is proposed, which combines the folding behavior observed in curved-crease origami and elastic shell buckling. This mechanism employs simple shell components, including internal diaphragms that undergo pseudofolding in a confined boundary condition to enable a snap-through transition. We reveal that the deployed tube is self-locked through geometrical interference, creating a braced tubular arrangement. This arrangement gives a direction-dependent structural performance, ranging from elastic response to crushing, thereby offering the potential for programmable structures. We demonstrate that our approach can advance existing deployment mechanisms (e.g., coiled and inflatable systems) and create diverse structural designs (e.g., metamaterials, adaptive structures, cantilevers, and lightweight panels).Weanticipate our design to be a starting point to drive technological advancement in real-world deployable tubular structures.
可展开的管状结构旨在实现功能扩展，有着广泛的应用，从柔性管道到刚性结构元件。这些从紧凑状态转变而来的结构，对于在工程和科学领域创建适应性解决方案至关重要。提高其性能的一个重大障碍是在可扩展性和刚度之间取得平衡。使用柔顺材料，这些结构比刚性机构能够实现更灵活的转变。然而，当受到外部压力（例如管壁载荷）时，它们通常会表现出刚度降低。在此，我们利用受折纸启发的技术和内部加强件来满足相互冲突的性能要求。我们提出了一种自锁机制，该机制结合了在曲线折痕折纸中观察到的折叠行为和弹性壳屈曲。这种机制采用简单的壳组件，包括在受限边界条件下经历伪折叠的内部隔膜，以实现快速通过转变。我们发现展开的管子通过几何干涉实现自锁，形成一种支撑管状结构。这种结构具有与方向相关的结构性能，范围从弹性响应到挤压，从而为可编程结构提供了潜力。我们证明我们的方法可以改进现有的展开机制（例如盘绕和充气系统），并创造出多样化的结构设计（例如超材料、自适应结构、悬臂和轻质面板）。我们预计我们的设计将成为推动实际可展开管状结构技术进步的起点。
