Department of Mechanical Engineering, Faculty of Engineering, Chiang Mai University, 239 Huay Kaew Rd., Chiang Mai 50200, Thailand.
LMGC, Université Montpellier, CNRS, Montpellier, France.
Phys Rev E. 2019 Jul;100(1-1):012904. doi: 10.1103/PhysRevE.100.012904.
Using bi-dimensional discrete element simulations, the shear strength and microstructure of granular mixtures composed of particles of different shapes are systematically analyzed as a function of the proportion of grains of a given number of sides and the combination of different shapes (species) in one sample. We varied the angularity of the particles by varying the number of sides of the polygons from 3 (triangles) up to 20 (icosagons) and disks. The samples analyzed were built keeping in mind the following cases: (1) increase of angularity and species starting from disks; (2) decrease of angularity and increase of species starting from triangles; (3) random angularity and increase of species starting from disks and from polygons. The results show that the shear strength vary monotonically with increasing numbers of species (it may increase or decrease), even in the random mixtures (case 3). At the micro-scale, the variation in shear strength as a function of the number of species is due to different mechanisms depending on the cases analyzed. It may result from the increase of both the geometrical and force anisotropies, from only a decrease of frictional anisotropy, or from compensation mechanisms involving geometrical and force anisotropies.
利用二维离散元模拟，系统地分析了由不同形状颗粒组成的颗粒混合物的抗剪强度和微观结构，作为具有给定边数的颗粒比例和一个样品中不同形状（种类）组合的函数。我们通过改变多边形的边数（从 3 个边（三角形）到 20 个边（二十面体））和圆盘来改变颗粒的棱角性。在分析样本时，我们考虑了以下情况：（1）从圆盘开始增加棱角性和种类；（2）从三角形开始降低棱角性并增加种类；（3）从圆盘和多边形开始随机增加棱角性和种类。结果表明，抗剪强度随着种类数量的增加单调变化（可能增加或减少），即使在随机混合物中（情况 3）也是如此。在微观尺度上，抗剪强度随种类数量的变化取决于分析情况的不同而有不同的机制。它可能是由于几何各向异性和力各向异性的增加引起的，也可能是由于涉及几何各向异性和力各向异性的补偿机制引起的，或者仅仅是由于摩擦各向异性的降低引起的。
