Popović Marko, de Geus Tom W J, Ji Wencheng, Wyart Matthieu
Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Phys Rev E. 2021 Aug;104(2-2):025010. doi: 10.1103/PhysRevE.104.025010.
Amorphous solids yield at a critical value Σ_{c} of the imposed stress Σ through a dynamical phase transition. While sharp in athermal systems, the presence of thermal fluctuations leads to the rounding of the transition and thermally activated flow even below Σ_{c}. Here we study the steady-state thermal flow of amorphous solids using a mesoscopic elastoplastic model. In the Hébraud-Lequex (HL) model we provide an analytical solution of the thermally activated flow at low temperature. We then propose a general scaling law that also describes the transition rounding. Finally, we find that the scaling law holds in numerical simulations of the HL model, a two-dimensional (2D) elastoplastic model, and previously published molecular dynamics simulations of 2D Lennard-Jones glass.
非晶态固体通过动态相变在施加应力Σ的临界值Σₑ处屈服。虽然在无热系统中转变是尖锐的，但热涨落的存在会导致转变变圆滑，甚至在Σₑ以下也会出现热激活流动。在这里，我们使用介观弹塑性模型研究非晶态固体的稳态热流。在赫布劳德 - 勒奎克斯（HL）模型中，我们给出了低温下热激活流动的解析解。然后，我们提出了一个通用的标度律，它也描述了转变的圆滑过程。最后，我们发现该标度律在HL模型（一个二维（2D）弹塑性模型）的数值模拟以及先前发表的二维 Lennard - Jones 玻璃的分子动力学模拟中均成立。
