Rheology and structure of granular materials near the jamming transition
Rheology and structure of granular materials near the jamming transition
复制标题
干扰转变附近颗粒材料的流变学和结构
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
F. Chevoir
中科院分区：
文献类型：
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作者：
P. Mills;P. Rognon;F. Chevoir
在堵塞过渡区附近的非粘性颗粒材料的剪切应力被认为与瞬时刚性颗粒簇的形成有关。这些瞬态集群的特性作为施加的压力，固体体积分数和剪切速率的函数进行了研究。这是负责的剪切应力为零的剪切速率，这导致了不稳定性接近堵塞过渡的增加。我们讨论了粘滑运动的后果，并沿斜面向下流动，与观测结果一致。然后，颗粒材料在两个堵塞流动状态之间的振荡产生快速的速度波动，这导致在流动方向上与相对于堵塞状态的平均速度成比例的平均摩擦力。因此，简单剪切流中的速度场由Brinkman方程控制，任何对称性破缺都有利于应变局部化。这种分析可以扩展到颗粒状糊状物的情况。
The shear stress of non-cohesive granular material in the vicinity of the jamming transition is supposed to be connected to the formation of transient rigid clusters of particles. The characteristics of these transient clusters are investigated as a function of the imposed pressure, the solid volume fraction and the shear rate. This is responsible for an increase of the shear stress for a vanishing shear rate, which leads to an instability close to the jamming transition. We discuss the consequences for stick-slip motion and flows down an inclined plane, in agreement with the observations. Then, the oscillation of the granular material between two jam-flow states generates fast velocity fluctuations which result in a mean frictional force proportional to the mean velocity relative to the jammed state in the flow direction. Accordingly the velocity field in a simple shear flow is governed by a Brinkman equation and any symmetry break favours a strain localization. This analysis might be extended to the case of granular pastes.