Effect of size polydispersity versus particle shape in dense granular media
Effect of size polydispersity versus particle shape in dense granular media
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DOI：
10.1103/physreve.90.012202
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发表时间：
2014-07-21
影响因子：
2.4
通讯作者：
Sornay, Philippe
中科院分区：
文献类型：
--
作者：
Nguyen, Duc-Hanh;Azema, Emilien;Sornay, Philippe
我们提出了一个详细的分析的颗粒系统组成的无摩擦五边形颗粒的形态，通过改变系统的尺寸跨度和颗粒形状的不规则性，这代表了两个多分散性参数的系统。微观结构的特征在于各种统计描述符，例如全局和局部堆积分数、径向分布函数、配位数和漂浮颗粒分数。我们发现，填充分数增加的两个参数的多分散性，但形状多分散性的影响，所有的调查结构性能是显着的，只有在低尺寸的多分散性的位置和/或取向有序的颗粒占上风。我们专注于更详细的类侧/侧接触，这是我们的系统相比，包装的磁盘有趣的功能。我们表明，这种接触的比例有弱的依赖性的多分散性参数。侧-侧接触不渗滤，但它们限定了作为尺寸多分散性的函数的增大的尺寸和作为形状多分散性的函数的减小的尺寸的簇。簇具有各向异性的形状，但随着多分散性的增加，纵横比减小。这一特征被认为是强力链（高于平均值的力）的结果，这主要是由侧-侧接触捕获的。最后，力的传递本质上是多尺度的，平均力随颗粒尺寸线性增加。
We present a detailed analysis of the morphology of granular systems composed of frictionless pentagonal particles by varying systematically both the size span and particle shape irregularity, which represent two polydispersity parameters of the system. The microstructure is characterized in terms of various statistical descriptors such as global and local packing fractions, radial distribution functions, coordination number, and fraction of floating particles. We find that the packing fraction increases with the two parameters of polydispersity, but the effect of shape polydispersity for all the investigated structural properties is significant only at low size polydispersity where the positional and/or orientational ordering of the particles prevail. We focus in more detail on the class of side/side contacts, which is the interesting feature of our system as compared to a packing of disks. We show that the proportion of such contacts has weak dependence on the polydispersity parameters. The side-side contacts do not percolate but they define clusters of increasing size as a function of size polydispersity and decreasing size as a function of shape polydispersity. The clusters have anisotropic shapes but with a decreasing aspect ratio as polydispersity increases. This feature is argued to be a consequence of strong force chains (forces above the mean), which are mainly captured by side-side contacts. Finally, the force transmission is intrinsically multiscale, with a mean force increasing linearly with particle size.