Origin of the Velocity-Strengthening Nature of Granular Friction
Origin of the Velocity-Strengthening Nature of Granular Friction
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DOI：
10.1007/s00024-011-0409-9
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发表时间：
2013-01-01
影响因子：
2
通讯作者：
Kuwano, Osamu
中科院分区：
文献类型：
--
作者：
Hatano, Takahiro;Kuwano, Osamu
本文提出了一种颗粒物质稳态动摩擦本构关系的简单理论。从能量平衡方程出发，结合晶粒动力学，估算了能量耗散率，直接导出了本构关系。结果表明，低密度的系统比高密度的系统更强，尽管有点违反直觉。这是由于导致能量耗散的颗粒重排在较低密度的系统中更频繁。因此，颗粒摩擦的速度强化性质自然地解释为密度的负剪切速率依赖性。本理论还定性地解释了实验观察到的较小层厚的系统趋于速度减弱。
A simple theory for a constitutive law for steady state dynamic friction in granular matter is presented. Starting from the energy balance equation together with the kinetics of grains, the energy dissipation rate is estimated, which directly leads to a constitutive law. The result indicates that a system of lower density is stronger than a system of higher density, albeit somewhat counterintuitive. This is a consequence of the fact that the grain rearrangement, which causes energy dissipation, is more frequent in a system of lower density. Thus, the velocity-strengthening nature of granular friction is naturally explained by the negative shear-rate dependence of the density. The present theory also qualitatively explains the experimental observation that a system of smaller layer thickness tends to be velocity-weakening.