An entirely stretchable origami inspired by pelican eels is unfolded and stretched to create adaptive, extreme shape morphing. Nature demonstrates adaptive and extreme shape morphing via unique patterns of movement. Many of them have been explained by monolithic shape-changing mechanisms, such as chemical swelling, skin stretching, origami/kirigami morphing, or geometric eversion, that were successfully mimicked in artificial analogs. However, there still remains an unexplored regime of natural morphing that cannot be reproduced in artificial systems by a “single-mode” morphing mechanism. One example is the “dual-mode” morphing of Eurypharynx pelecanoides (commonly known as the pelican eel), which first unfolds and then inflates its mouth to maximize the probability of engulfing the prey. Here, we introduce pelican eel–inspired dual-morphing architectures that embody quasi-sequential behaviors of origami unfolding and skin stretching in response to fluid pressure. In the proposed system, fluid paths were enclosed and guided by a set of entirely stretchable origami units that imitate the morphing principle of the pelican eel’s stretchable and foldable frames. This geometric and elastomeric design of fluid networks, in which fluid pressure acts in the direction that the whole body deploys first, resulted in a quasi-sequential dual-morphing response. To verify the effectiveness of our design rule, we built an artificial creature mimicking a pelican eel and reproduced biomimetic dual-morphing behavior. By compositing the basic dual-morphing unit cells into conventional origami frames, we demonstrated architectures of soft machines that exhibit deployment-combined adaptive gripping, crawling, and large range of underwater motion. This design principle may provide guidance for designing bioinspired, adaptive, and extreme shape-morphing systems.

中文翻译：

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生物启发的双变形可拉伸折纸

展开并拉伸受鹈鹕鳗启发的完全可拉伸的折纸，以创建自适应的极端形状变形。大自然通过独特的运动模式表现出自适应和极端的形状变形。它们中的许多已通过整体形状改变机制进行了解释，例如化学溶胀，皮肤拉伸，折纸/折纸变形或几何外翻，这些已在人工类似物中成功模仿。但是，仍然存在未经探索的自然变形机制，无法通过“单模”变形机制在人工系统中进行复制。一个例子是Eurypharynx pelecanoides（通常称为鹈鹕鳗）的“双模”变形，该变形首先展开，然后膨胀其嘴，以最大程度地吞噬猎物。这里，我们介绍了鹈鹕鳗鱼启发的双重变形架构，该架构体现了折纸展开和响应流体压力的皮肤拉伸的准顺序行为。在提出的系统中，流体路径被一组完全可拉伸的折纸单元包围并引导，这些单元模仿了鹈鹕鳗鱼可拉伸和可折叠框架的变形原理。流体网络的这种几何和弹性设计（其中流体压力首先沿整个身体展开的方向起作用）导致了准顺序的双重变形响应。为了验证我们的设计规则的有效性，我们构建了一个模仿鹈鹕鳗的人工生物，并复制了仿生双重形态行为。通过将基本的双重变形单位细胞合成到传统的折纸框架中，我们演示了展示结合部署的自适应抓取，爬行和大范围水下运动的软机体系结构。该设计原则可以为设计生物启发性，自适应性和极端形状变形系统提供指导。