Structural mechanics and helical geometry of thin elastic composites
Structural mechanics and helical geometry of thin elastic composites
复制标题
薄弹性复合材料的结构力学和螺旋几何形状
DOI：
10.1039/c6sm01090c
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发表时间：
2016
期刊：
影响因子：
3.4
通讯作者：
Hirofumi Wada
中科院分区：
文献类型：
--
作者：
M. Tsuchiya;A. Tanaka;M. Yasuda;T. Harada;S. Cho;and M. Yokoyama;Hirofumi Wada
螺旋在自然界中是普遍存在的，并且螺旋形状转变经常在残余应力体（诸如复合材料）中观察到，其中具有不同机械性质的材料牢固地胶合在一起以形成整体。受到各种生物学例子的启发，人们已经广泛研究了这种薄复合结构中出现扭曲和弯曲的基本物理机制。在这里，我们提出了一个简化的分析模型，其中一个细长的膜管进行螺旋过渡驱动的弹性带约束到膜表面的收缩。我们分析预测的曲率和扭曲的紧急螺旋线的微分应变和弹性模量的函数，这证实了我们的数值模拟。我们的研究结果可能有助于理解在不同生物系统中观察到的形状，例如螺旋细菌，并可应用于软机器和机器人的新设计。
Helices are ubiquitous in nature, and helical shape transition is often observed in residually stressed bodies, such as composites, wherein materials with different mechanical properties are glued firmly together to form a whole body. Inspired by a variety of biological examples, the basic physical mechanism responsible for the emergence of twisting and bending in such thin composite structures has been extensively studied. Here, we propose a simplified analytical model wherein a slender membrane tube undergoes a helical transition driven by the contraction of an elastic ribbon bound to the membrane surface. We analytically predict the curvature and twist of an emergent helix as functions of differential strains and elastic moduli, which are confirmed by our numerical simulations. Our results may help understand shapes observed in different biological systems, such as spiral bacteria, and could be applied to novel designs of soft machines and robots.