Department of Physics and Astronomy, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4.
Phys Rev E. 2019 Dec;100(6-1):063003. doi: 10.1103/PhysRevE.100.063003.
We report on a particle-based numerical study of sheared amorphous solids in the dense slow flow regime. In this framework, deformation and flow are accompanied by critical fluctuation patterns associated with the macroscopic plastic response. The former is commonly attributed to the collective slip patterns that relax internal stresses within the bulk material and give rise to an effective mechanical noise governing the latter particle-level process. In this paper, the avalanche-type dynamics between plastic events is shown to have a strong relevance on the self-diffusion of tracer particles in the Fickian regime. As a consequence, strong size effects emerge in the effective diffusion coefficient that is rationalized in terms of avalanche size distributions and the relevant temporal occurrence.
我们报告了一个基于粒子的数值研究，研究了密集缓慢流动状态下的剪切无定形固体。在这个框架中，变形和流动伴随着与宏观塑性响应相关的临界波动模式。前者通常归因于集体滑动模式，这些模式可以在大块材料内部松弛内应力，并产生控制后者颗粒级过程的有效机械噪声。在本文中，显示了在塑性事件之间的雪崩型动力学与示踪粒子在菲克定律区域的自扩散之间具有很强的相关性。因此，在有效扩散系数中出现了强烈的尺寸效应，这可以根据雪崩尺寸分布和相关的时间发生来合理化。
