Basak Rituparna, Kozlowski Ryan, Pugnaloni Luis A, Kramar M, Socolar Joshua E S, Carlevaro C Manuel, Kondic Lou
Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey 07102, USA.
Department of Physics, College of the Holly Cross, Worcester, Massachusetts 01610, USA.
Phys Rev E. 2023 Nov;108(5-1):054903. doi: 10.1103/PhysRevE.108.054903.
In quasi-two-dimensional experiments with photoelastic particles confined to an annular region, an intruder constrained to move in a circular path halfway between the annular walls experiences stick-slip dynamics. We discuss the response of the granular medium to the driven intruder, focusing on the evolution of the force network during sticking periods. Because the available experimental data do not include precise information about individual contact forces, we use an approach developed in our previous work [Basak et al., J. Eng. Mech. 147, 04021100 (2021)0733-939910.1061/(ASCE)EM.1943-7889.0002003] based on networks constructed from measurements of the integrated strain magnitude on each particle. These networks are analyzed using topological measures based on persistence diagrams, revealing that force networks evolve smoothly but in a nontrivial manner throughout each sticking period, even though the intruder and granular particles are stationary. Characteristic features of persistence diagrams show identifiable slip precursors. In particular, the number of generators describing the structure and complexity of force networks increases consistently before slips. Key features of the dynamics are similar for granular materials composed of disks or pentagons, but some details are consistently different. In particular, we find significantly larger fluctuations of the measures computed based on persistence diagrams and, therefore, of the underlying networks, for systems of pentagonal particles.
在光弹性颗粒被限制在环形区域的准二维实验中，一个被限制在环形壁之间中间位置做圆周运动的入侵者会经历粘滑动力学。我们讨论了颗粒介质对驱动入侵者的响应，重点关注粘着期内力网络的演变。由于现有的实验数据不包括关于单个接触力的精确信息，我们采用了我们之前工作[巴萨克等人，《工程力学杂志》147，04021100 (2021)0733 - 939910.1061/(ASCE)EM.1943 - 7889.0002003]中开发的一种方法，该方法基于从每个颗粒上的积分应变大小测量构建的网络。使用基于持久图的拓扑度量对这些网络进行分析，结果表明，即使入侵者和颗粒静止不动，力网络在每个粘着期内也会以一种非平凡的方式平稳演化。持久图的特征显示出可识别的滑动前兆。特别是，描述力网络结构和复杂性的生成元数量在滑动之前持续增加。对于由圆盘或五边形组成的颗粒材料，动力学的关键特征相似，但一些细节始终不同。特别是，我们发现对于五边形颗粒系统，基于持久图计算的度量以及因此底层网络的波动明显更大。
