Azéma Emilien, Linero Sandra, Estrada Nicolas, Lizcano Arcesio
Laboratoire de Mécanique et Génie Civil (LMGC), Université de Montpellier, CNRS, Montpellier, France.
University of Newcastle, Faculty of Engineering and Build Environment, University Dr Callaghan NSW2308, Australia.
Phys Rev E. 2017 Aug;96(2-1):022902. doi: 10.1103/PhysRevE.96.022902. Epub 2017 Aug 14.
By means of extensive contact dynamics simulations, we analyzed the effect of particle size distribution (PSD) on the strength and microstructure of sheared granular materials composed of frictional disks. The PSDs are built by means of a normalized β function, which allows the systematic investigation of the effects of both, the size span (from almost monodisperse to highly polydisperse) and the shape of the PSD (from linear to pronouncedly curved). We show that the shear strength is independent of the size span, which substantiates previous results obtained for uniform distributions by packing fraction. Notably, the shear strength is also independent of the shape of the PSD, as shown previously for systems composed of frictionless disks. In contrast, the packing fraction increases with the size span, but decreases with more pronounced PSD curvature. At the microscale, we analyzed the connectivity and anisotropies of the contacts and forces networks. We show that the invariance of the shear strength with the PSD is due to a compensation mechanism which involves both geometrical sources of anisotropy. In particular, contact orientation anisotropy decreases with the size span and increases with PSD curvature, while the branch length anisotropy behaves inversely.
通过广泛的接触动力学模拟，我们分析了粒度分布（PSD）对由摩擦盘组成的剪切颗粒材料的强度和微观结构的影响。PSD通过归一化的β函数构建，这使得能够系统地研究尺寸跨度（从几乎单分散到高度多分散）和PSD形状（从线性到明显弯曲）的影响。我们表明，剪切强度与尺寸跨度无关，这证实了先前通过堆积分数对均匀分布获得的结果。值得注意的是，剪切强度也与PSD的形状无关，正如先前对由无摩擦盘组成的系统所表明的那样。相比之下，堆积分数随尺寸跨度增加，但随PSD曲率增加而减小。在微观尺度上，我们分析了接触和力网络的连通性和各向异性。我们表明，剪切强度随PSD的不变性是由于一种补偿机制，该机制涉及各向异性的两个几何来源。特别是，接触取向各向异性随尺寸跨度减小而随PSD曲率增加，而分支长度各向异性则相反。
