Department of Physics and Center for Nonlinear and Complex Systems, Duke University, Durham, North Carolina 27708, USA.
Key Laboratory of Mechanics on Western Disaster and Environment, Ministry of Education of China, Lanzhou University, 730000 Lanzhou, China.
Phys Rev E. 2017 Nov;96(5-1):052902. doi: 10.1103/PhysRevE.96.052902. Epub 2017 Nov 6.
We present the experimental and numerical studies of a two-dimensional sheared amorphous material composed of bidisperse photoelastic disks. We analyze the statistics of avalanches during shear including the local and global fluctuations in energy and changes in particle positions and orientations. We find scale-free distributions for these global and local avalanches denoted by power laws whose cutoffs vary with interparticle friction and packing fraction. Different exponents are found for these power laws depending on the quantity from which variations are extracted. An asymmetry in time of the avalanche shapes is evidenced along with the fact that avalanches are mainly triggered by the shear bands. A simple relation independent of the intensity is found between the number of local avalanches and the global avalanches they form. We also compare these experimental and numerical results for both local and global fluctuations to predictions from mean-field and depinning theories.
我们提出了一种由双分散光弹性盘组成的二维剪切非晶材料的实验和数值研究。我们分析了剪切过程中包括能量的局部和全局波动以及颗粒位置和取向变化的雪崩统计。我们发现这些全局和局部雪崩的无标度分布用幂律表示，其截止值随颗粒间摩擦和堆积分数而变化。根据提取变化的数量，这些幂律的指数不同。沿着剪切带主要触发雪崩的事实，证明了雪崩形状在时间上存在不对称性。还发现了局部雪崩的数量与它们形成的全局雪崩之间的简单关系，该关系与强度无关。我们还将这些实验和数值结果与平均场和去钉扎理论的局部和全局波动预测进行了比较。
