Stress Analysis of a Sheared Athermal System with Pins

Numerous studies have investigated the jamming transition in granular media. Recent research has indicated that quenched disorder in the form of fixed pins provide additional stabilizing forces to the system, which causes the jamming threshold to decrease and therefore provides a fourth degree of freedom in the jamming transition. Using molecular dynamics simulations, we study a two-dimensional, granular system subjected to a wall-driven flow in the vicinity of jamming in order to understand how pins affect the dynamics of the system. We implement a shear by freezing the top and bottom of the binary mixture, and move the walls at a constant shear rate. The system is a 50:50 binary mixture with purely repulsive harmonic interactions of size ratio 0.004:1:1.4 of pins:small:large particles. Pins are located on a square lattice. We will present results concerning shear stress and pressure as a function of packing fraction and strain rate. We will also show preliminary results for the statistics of the shear stress as function of time.