Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, United Kingdom.
Phys Rev Lett. 2012 Feb 17;108(7):078101. doi: 10.1103/PhysRevLett.108.078101. Epub 2012 Feb 13.
A general continuum theory for the distribution of hairs in a bundle is developed, treating individual fibers as elastic filaments with random intrinsic curvatures. Applying this formalism to the iconic problem of the ponytail, the combined effects of bending elasticity, gravity, and orientational disorder are recast as a differential equation for the envelope of the bundle, in which the compressibility enters through an "equation of state." From this, we identify the balance of forces in various regions of the ponytail, extract a remarkably simple equation of state from laboratory measurements of human ponytails, and relate the pressure to the measured random curvatures of individual hairs.
本文发展了一种描述毛发束中毛发分布的广义连续统理论，将单个纤维视为具有随机固有曲率的弹性细丝。将该形式体系应用于马尾辫这一典型问题，弯曲弹性、重力和取向无序的综合效应被重新表述为束的包络的微分方程，其中可压缩性通过“状态方程”进入。由此，我们确定了马尾辫各个区域的力平衡，从对人马尾辫的实验室测量中提取出一个非常简单的状态方程，并将压力与个体毛发的测量随机曲率联系起来。
