Unfolding the Sulcus
Unfolding the Sulcus
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DOI：
10.1103/physrevlett.106.105702
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发表时间：
2011-03-07
影响因子：
8.6
通讯作者：
Mahadevan, L.
中科院分区：
文献类型：
--
作者：
Hohlfeld, Evan;Mahadevan, L.
沟是软质材料表面由压缩引起的不稳定性而形成的局部沟壑。我们通过打破它的自然尺度和平移不变性来展开这种不稳定性，并计算出sulcfication的极限分岔图，表明它是一种无尺度的亚临界非线性不稳定性。与经典成核相反，硫酸化是连续的，发生在纯弹性连续体中，在表面能消失的极限下结构稳定。在加载过程中，沟槽在具有较高临界应变和线性化谱的基本奇点处形成核。在卸载时，它准静态收缩到具有较低临界应变的点，这可以用尺度对称的破坏来解释。在中间应变下，系统是线性稳定的，但非线性不稳定，没有能垒。简单的实验证实了这两个临界菌株的存在。
Sulci are localized furrows on the surface of soft materials that form by a compression-induced instability. We unfold this instability by breaking its natural scale and translation invariance, and compute a limiting bifurcation diagram for sulcfication showing that it is a scale-free, subcritical nonlinear instability. In contrast with classical nucleation, sulcification is continuous, occurs in purely elastic continua and is structurally stable in the limit of vanishing surface energy. During loading, a sulcus nucleates at a point with an upper critical strain and an essential singularity in the linearized spectrum. On unloading, it quasistatically shrinks to a point with a lower critical strain, explained by breaking of scale symmetry. At intermediate strains the system is linearly stable but nonlinearly unstable with no energy barrier. Simple experiments confirm the existence of these two critical strains.