Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
School of Math, Science, and Engineering, Central New Mexico Community College, Albuquerque, New Mexico 87106, USA.
Phys Rev Lett. 2019 Feb 1;122(4):048003. doi: 10.1103/PhysRevLett.122.048003.
The transition between shear-flowing and shear-arrested states of frictional granular matter is studied using constant-stress discrete element simulations. By subjecting a dilute system of frictional grains to a constant external shear stress and pressure, friction-dependent critical shear stress and density are clearly identified with both exhibiting a crossover between low and high friction. The critical shear stress bifurcates two nonequilibrium steady states: (i) steady state shear flow characterized by a constant deformation rate, and (ii) shear arrest characterized by temporally decaying creep to a statically stable state. The onset of arrest below critical shear stress occurs at a time t_{c} that exhibits a heavy-tailed distribution, whose mean and variance diverge as a power law at the critical shear stress with a friction-dependent exponent that also exhibits a crossover between low and high friction. These observations indicate that granular arrest near critical shear stress is highly unpredictable and is strongly influenced by interparticle friction.
使用恒应力离散元模拟研究了摩擦性颗粒物质从剪切流动到剪切停止状态的转变。通过对摩擦性颗粒的稀化系统施加恒定的外部剪切应力和压力，明显确定了摩擦相关的临界剪切应力和密度，两者都表现出在低摩擦和高摩擦之间的交叉。临界剪切应力分叉出两个非平衡稳态：（i）以恒定变形率为特征的稳态剪切流动，以及（ii）以时间衰减的蠕动到静态稳定状态为特征的剪切停止。在临界剪切应力以下，停止的起始发生在时间 t_{c}，其表现出重尾分布，其平均值和方差随着临界剪切应力的幂律发散，摩擦相关的指数也在低摩擦和高摩擦之间表现出交叉。这些观察结果表明，接近临界剪切应力的颗粒停止是高度不可预测的，并且受到颗粒间摩擦的强烈影响。
