论文标题
在机械训练的无摩擦颗粒中剪切干扰和剪切熔化
Shear jamming and shear melting in mechanically trained frictionless particles
论文作者
论文摘要
我们通过考虑机械训练对干扰过渡和非线性流变性的影响，研究静态系统和剪切剪切系统的临界性。我们使用经过静止的准静态循环体积变形的初始构型模拟了经历静脉化准静态剪切的无摩擦软颗粒。初始配置的干扰过渡密度$φ_ {\ rm j0} $通过调整机械训练的``深度''来系统地改变。我们在这些构型上发挥稳定的剪切作用，并观察剪切干扰（剪切引起的刚度）或剪切熔化（由于剪切而导致的刚度损失），具体取决于训练的深度和与堵塞过渡密度的接近性。我们还观察到，在剪切干扰或熔化的特征菌株以唯一密度$φ_ {\ rm js} $差异。这是由于干扰过渡密度从$φ_ {\ rm j0} $转移到剪切下的$φ_ {\ rm js} $，与初始配置失去记忆有关。最后，我们彻底研究了堵塞过渡密度附近的非线性流变学，与以前的工作相反，我们发现非线性``软化''发生在下面的下方以及上面的堵塞过渡密度上方。
We investigate criticality near the jamming transition in both quiescent systems and those under shear by considering the effect of mechanical training on the jamming transition and nonlinear rheology. We simulate frictionless soft particles undergoing athermal quasi-static shear using initial configurations trained with athermal quasi-static cyclic volume deformations. The jamming transition density of the initial configuration $φ_{\rm J0}$ is systematically altered by tuning the ``depth'' of mechanical training. We exert a steady shear on these configurations and observe either shear jamming (gain of stiffness due to shear) or shear melting (loss of stiffness due to shear), depending on the depth of training and proximity to the jamming transition density. We also observe that the characteristic strains, at which shear jamming or melting occur, diverge at a unique density $φ_{\rm JS}$. This is due to the shift of the jamming transition density from $φ_{\rm J0}$ to $φ_{\rm JS}$ under shear, associated with loss of memory of the initial configuration. Finally, we thoroughly investigate nonlinear rheology near the jamming transition density, and contrary to previous works, we find a nonlinear ``softening'' takes place below as well as above the jamming transition density.
