Geometry underlies the mechanical stiffening and softening of an indented floating film
Geometry underlies the mechanical stiffening and softening of an indented floating film
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DOI：
10.1039/d0sm00250j
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发表时间：
2020-05-07
期刊：
影响因子：
3.4
通讯作者：
Paulsen, Joseph D.
中科院分区：
文献类型：
--
作者：
Ripp, Monica M.;Demery, Vincent;Paulsen, Joseph D.
无定形各向同性固体的胡克力学的一个基本范例是，小变形与外力的大小成比例。然而，即使在微小的力作用下，细长体也可能发生大的变形，导致源于纯粹几何效应的非线性响应。在这里，我们研究的压痕的聚合物薄膜上的液体浴。我们的实验和模拟支持最近预测的硬化响应[D.维拉和B。Davidovitch，Phys. Rev. E，2018，98，013003]，并且我们表明该系统在大斜率下软化，与我们解决小挠度和大挠度的理论一致。我们展示了如何硬化和软化来自非平凡的，但通用的功能的应力和位移场。
A basic paradigm underlying the Hookean mechanics of amorphous, isotropic solids is that small deformations are proportional to the magnitude of external forces. However, slender bodies may undergo large deformations even under minute forces, leading to nonlinear responses rooted in purely geometric effects. Here we study the indentation of a polymer film on a liquid bath. Our experiments and simulations support a recently-predicted stiffening response [D. Vella and B. Davidovitch, Phys. Rev. E, 2018, 98, 013003], and we show that the system softens at large slopes, in agreement with our theory that addresses small and large deflections. We show how stiffening and softening emanate from nontrivial yet generic features of the stress and displacement fields.