Ekeh Timothy, Fodor Étienne, Fielding Suzanne M, Cates Michael E
DAMTP, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, United Kingdom.
Department of Physics and Materials Science, University of Luxembourg, L-1511 Luxembourg, Luxembourg.
Phys Rev E. 2022 May;105(5):L052601. doi: 10.1103/PhysRevE.105.L052601.
The importance of mesoscale fluctuations in flowing amorphous materials is widely accepted, without a clear understanding of their role. We propose a mean-field elastoplastic model that admits both stress and strain-rate fluctuations, and investigate the character of its power distribution under steady shear flow. The model predicts the suppression of negative power fluctuations near the liquid-solid transition; the existence of a fluctuation relation in limiting regimes but its replacement in general by stretched-exponential power-distribution tails; and a crossover between two distinct mechanisms for negative power fluctuations in the liquid and the yielding solid phases. We connect these predictions with recent results from particle-based, numerical microrheological experiments.
中尺度涨落在流动非晶态材料中的重要性已得到广泛认可，但人们对其作用仍缺乏清晰的认识。我们提出了一个允许应力和应变率涨落的平均场弹塑性模型，并研究了其在稳定剪切流作用下的功率分布特性。该模型预测了在液 - 固转变附近负功率涨落的抑制；在极限情况下涨落关系的存在，但在一般情况下被拉伸指数功率分布尾部所取代；以及在液相和屈服固相阶段负功率涨落的两种不同机制之间的转变。我们将这些预测与基于粒子的数值微观流变学实验的最新结果联系起来。
