Department of Physics, Faculty of Science, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto, 603-8555, Japan.
Eur Phys J E Soft Matter. 2021 Jun 24;44(6):85. doi: 10.1140/epje/s10189-021-00089-8.
We investigate statistics and scaling laws of avalanches in two-dimensional frictional particles by numerical simulations. We find that the critical exponent for avalanche size distributions is governed by microscopic friction between the particles in contact, where the exponent is larger and closer to mean-field predictions if the friction coefficient is finite. We reveal that microscopic "slips" between frictional particles induce numerous small avalanches which increase the slope, as well as the power-law exponent, of avalanche size distributions. We also analyze statistics and scaling laws of the avalanche duration and maximum stress drop rates, and examine power spectra of stress drop rates. Our numerical results suggest that the microscopic friction is a key ingredient of mean-field descriptions and plays a crucial role in avalanches observed in real materials.
我们通过数值模拟研究了二维摩擦颗粒中雪崩的统计和标度律。我们发现，雪崩大小分布的临界指数由接触颗粒之间的微观摩擦力控制，如果摩擦系数有限，则指数更大且更接近平均场预测。我们揭示了摩擦颗粒之间的微观“滑动”会引发大量小雪崩，从而增加雪崩大小分布的斜率和幂律指数。我们还分析了雪崩持续时间和最大应力降速率的统计和标度律，并研究了应力降速率的功率谱。我们的数值结果表明，微观摩擦力是平均场描述的关键因素，在实际材料中观察到的雪崩中起着至关重要的作用。
