Geometric aspects of shear jamming induced by deformation of frictionless sphere packings
Geometric aspects of shear jamming induced by deformation of frictionless sphere packings
复制标题
无摩擦球填料变形引起的剪切干扰的几何方面
DOI：
10.1088/1742-5468/2016/09/094002
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
S. Sastry
中科院分区：
文献类型：
--
作者：
H. A. Vinutha;S. Sastry
最近已经证明，无摩擦球形填料的剪切变形导致在存在摩擦的情况下，在远低于各向同性堵塞点的密度下以及在足够高的应变下将经历堵塞的结构。在这里，我们表明，应变引起的几何特征是强大的相对于有限的尺寸效应，并包括超均匀性的功能，以前研究的背景下，干扰，最近在驱动系统。我们研究的方法，以堵塞应变增加，通过摩擦动力学发展无摩擦剪切配置，从而确定一个关键的，或堵塞，应变为每个密度，为选定的值的摩擦系数。当摩擦力超过一定的应变值时，剪切的无摩擦填料开始产生有限的应力，这标志着剪切堵塞的开始。在较高的应变值，剪切应力达到饱和值后，迅速上升超过剪切堵塞的开始，这允许识别的剪切堵塞过渡。当配位数Z = 3和Z = 4时，剪切堵塞和剪切堵塞开始发生。通过考虑渗流概率的接触网络，集群的四个协调和六个协调的领域，我们表明，渗流的四个协调的领域对应于剪切干扰行为的发病，而渗流的六个协调的领域对应于剪切干扰，为选定的摩擦系数。在发生剪切堵塞时，力的分布开始在有限值处形成峰值，力网络是各向异性和非均匀的。而在剪切阻塞过渡处，力分布有一个很好的峰值，接近峰值，力网络的各向异性和均匀性较小。我们简要讨论了机械方面的干扰行为进行正常模式分析和计算剪切模量。
It has recently been demonstrated that shear deformation of frictionless sphere packings leads to structures that will undergo jamming in the presence of friction, at densities well below the isotropic jamming point ϕj≈0.64, and at high enough strains. Here, we show that the geometric features induced by strain are robust with respect to finite size effects, and include the feature of hyperuniformity, previously studied in the context of jamming, and more recently in driven systems. We study the approach to jamming as strain is increased, by evolving frictionless sheared configurations through frictional dynamics, and thereby identify a critical, or jamming, strain for each density, for a chosen value of the coefficient of friction. In the presence of friction above a certain strain value the sheared frictionless packings begin to develop finite stresses, which marks the onset of shear jamming. At a higher strain value, the shear stress reaches a saturation value after rising rapidly above the onset of shear jamming, which permits identification of the shear jamming transition. The onset of shear jamming and shear jamming are found to occur when the coordination number Z reaches values of Z = 3 and Z = 4 respectively. By considering percolation probabilities for the contact network, clusters of four coordinated and six coordinated spheres, we show that the percolation of four coordinated spheres corresponds to the onset of shear jamming behaviour, whereas the percolation of six coordinated spheres corresponds to shear jamming, for the chosen friction coefficients. At the onset of shear jamming, the force distribution begins to develop a peak at finite value and the force network is anisotropic and heterogeneous. And at the shear jamming transition, the force distribution has a well defined peak close to 〈 f〉 and the force network is less anisotropic and homogeneous. We briefly discuss mechanical aspects of the jamming behaviour by performing normal mode analysis and computing shear modulus.