标题： 弹性丝中的捆绑结构与施加的扭力 显示英文标题

标题： Bundling architecture in elastic filaments with applied twist

摘要： 我们研究了螺旋多纤维束的形成以及达到它们所需的扭矩随施加扭力的变化情况。 具有圆形截面的超弹性纤维平行安装在端夹上，这些端夹可以沿着扭力轴移动，具体取决于施加的轴向载荷。 随着扭力的增加，纤维在以圆圈形式接触之前描述了一个双曲双曲面，然后随着扭力的增加，在中心紧密地包装成一个螺旋束。 虽然对于足够小的纤维数量，束看起来是有序的，但对于足够大的纤维数量和施加的扭力，它们是无序的。 我们通过X射线断层扫描发现，纤维的排列变得无序，这是由于径向不稳定性导致束半径减小，并且纤维在束内相互迁移。 尽管如此，束中纤维的螺旋角被发现基本上是恒定的，导致倾斜角随着远离旋转轴的距离而增加。 我们开发了能量最小化分析，以捕捉考虑到纤维的neo-Hookean性质时，束长度和扭矩随纤维数量变化的观察到的变化。 我们表明，束的几何形状和施加的载荷可以用来描述作为扭力角度函数测量的非线性扭矩曲线。 显示英文摘要

摘要： We investigate the formation of helical multifilament bundles and the torque required to achieve them as a function of applied twist. Hyperelastic filaments with circular cross sections are mounted parallel in a uniform circle onto end-clamps that can move along the twist axis depending on the applied axial load. With increasing twist, the filaments describe a hyperbolic hyperboloid surface before coming into contact in a circle, and then packing in a tight helical bundle in the center with increasing twist. While the bundle appears ordered for sufficiently small number of filaments, they are disordered for large enough number of filaments and applied twist. We reveal with x-ray tomography, that the packing of the filaments becomes disordered following a radial-instability which leads to a decrease in bundle radius, and migration of filaments relative to each other in the bundle. Nonetheless, the helical angle of the filaments in the bundle are found to be essentially constant, resulting in inclination angles which increase with distance from axis of rotation. We develop energy minimization analysis to capture the observed variations in bundle length and torque as a function of number of filaments considering the neo-Hookean nature of the filaments. We show that the bundle geometry and the applied load can be used to describe the non-linear torque profile measured as a function of twist angle.