Recent advances in understanding deformation and flow of granular matter

• Main Author: Mesarović Siniša Đ.
• Format: Article
• Language: English
• Published: Faculty of civil engineering, Subotica 2014-01-01
• Series: Zbornik Radova Građevinskog Fakulteta
• Subjects: Dilatancy; shear bands; vortex flow; length scale
• Online Access: http://scindeks-clanci.ceon.rs/data/pdf/0352-6852/2014/0352-68521424027M.pdf

By means of graph theory, we analyze the changes in topology of a granular assembly during deformation. The elementary mechanism of diffuse deformation consists of intermittent flips. We show that dilatancy is the direct result of: an increasing number of flips, and, elastic relaxation of particles upon flips. Both are dependent on particles' elastic potential energy prior to flip and after the flip. The latter is the result of non uniform distribution of interparticle forces in force chains. Next, we consider shear bands in granular materials. Formation of shear bands is accompanied by accompanied by massive rolling of particle. Since rolling is constrained by neighbors, a characteristic rolling correlation length appears. The transmission of rotations in a particular direction depends on the strength of the force chain branches in the direction of propagation and across. The maximum propagation distance is comparable to observed widths of shear bands. Finally, we turn to the question of vortex formation within shear bands and argue that vortex pattern minimizes the dissipation/resistance in granular fluid.