Shear-Jamming in Two-Dimensional Granular Materials with Power-Law Grain-Size Distribution

Abstract

Although substantial progress has been made in recent years in research onsheared granular matter, relatively few studies concentrate on the behavior of materials withvery strong polydispersity. In this paper, shear deformation of a two-dimensional granularmaterial composed of frictional disk-shaped grains with power-law size distribution isanalyzed numerically with a finite-difference model. The analysis of the results concentrateson those aspects of the behavior of the modeled system that are related to its polydispersity. Itis demonstrated that many important global material properties are dependent on the behaviorof the largest grains from the tail of the size distribution. In particular, they are responsiblefor global correlation of velocity anomalies emerging at the jamming transition. They alsobuild a skeleton of the global contact and force networks in shear-jammed systems, leadingto the very open, “sparse” structure of those networks, consisting of only ~ 35% of all grains.The details of the model are formulated so that it represents fragmented sea ice moving ona two-dimensional sea surface; however, the results are relevant for other types of stronglypolydisperse granular materials, as well.

Keywords

• granular materials
• finite-element simulation
• shear deformation
• jamming phase transition
• polydispersity
• force networks