Granular systems are a rich and interesting topic of study in condensed matter physics. Working with Dave Egolf at Georgetown, I studied the dynamics of dense 2D sheared granular systems. As shown below, when granular systems are sheared, the shear stress gets distributed heterogeneously throughout the medium, thereby forming stress chains. In the image below from our MD simulations, red indicates high stress and blue indicates low stress.
We have found that nonlinear dynamical quantities, the Lyapunov exponents and vectors, are correlated with rearrangement and stress-release events during shearing. This raises the exciting possibility that these cooperative dynamical modes can be used to predict the spatiotemporal locations of earthquake-like events. Additionally, we find that these quantities are associated with time and length scales that diverge as the packing fraction the jamming density.
References
- EJ Banigan, MK Illich, DJ Stace-Naughton, and DA Egolf (2013) The chaotic dynamics of jamming. Nat. Phys. 9: 288-292.
- T. Shinbrot (2013) Granular matter: the movable and the jammed. Nat. Phys. 9:263-264.