Stress transmission in systems of faceted particles in a silo: the roles of filling rate and particle aspect ratio
Stress transmission in systems of faceted particles in a silo: the roles of filling rate and particle aspect ratio
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DOI：
10.1007/s10035-014-0509-1
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发表时间：
2014-05
期刊：
影响因子：
2.4
通讯作者：
M. Acevedo;I. Zuriguel;D. Maza;Ignacio Pagonabarraga;F. Alonso-marroquin;R. Hidalgo
中科院分区：
文献类型：
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作者：
M. Acevedo;I. Zuriguel;D. Maza;Ignacio Pagonabarraga;F. Alonso-marroquin;R. Hidalgo
我们提出了实验和数值计算结果的颗粒排列和应力分布在包装的小规模的二维筒仓沉积的多面颗粒。首先，我们实验表征的沉积物的形态方面的颗粒的纵横比和进料速率。然后，我们使用实验结果来验证我们的离散元方法（DEM）的基础上球多面体。在取得了很好的一致性后，我们使用模拟提供的接触力和织物来计算粗粒度的应力张量。对于低进料速率，方形颗粒显示出向下排列的强烈趋势，即，对角线平行于重力。这种形态导致应力向壁传递，这意味着压力饱和的快速发展，与杨森效应一致。当进料速率增加时，筒仓中的无序度和水平方形的数量都增加，从而阻碍了杨森效应。相反，对于细长颗粒，进料速率对最终存款性质的影响很弱。事实上，我们总是观察到高度有序的水平杆结构，其中应力主要在垂直方向上传递。
We present experimental and numerical results for particle alignment and stress distribution in packings of faceted particles deposited in a small-scale bi-dimensional silo. First, we experimentally characterize the deposits’ morphology in terms of the particles’ aspect ratio and feeding rate. Then we use the experimental results to validate our discrete element method (DEM) based on spheropolygons. After achieving excellent agreement, we use contact forces and fabric provided by the simulations to calculate the coarse-grained stress tensor. For low feeding rates, square particles display a strong tendency to align downwards, i.e., with a diagonal parallel to gravity. This morphology leads to stress transmission towards the walls, implying a quick development of pressure saturation, in agreement with the Janssen effect. When the feed rate is increased, both the disorder and the number of horizontal squares in the silo increase, hindering the Janssen effect. Conversely, for elongated particles the feed rate has a weak effect on the final deposit properties. Indeed, we always observe highly ordered structures of horizontal rods where the stress is transmitted mainly in the vertical direction.