LOCAL DESCRIPTION OF FRICTIONAL WEAKENING IN VIBRATED GRANULAR SHEAR FLOWS

Abstract

The rheology of vibrated granular shear flows is a key missing piece for modeling and predicting landslides, earthquakes, and more. In this thesis, we use computer simulations written in the Large-scale Atomic/Molecular Multiprocessor Parallel Simulator (LAMMPS) language to study frictional properties of vibrated granular shear flows subjected to externally applied vibrations at the lower boundary. Based on previous dimensional analysis and the Discrete Element Method (DEM) simulations from LAMMPS, we examine frictional weakening at the local grain-scale, correlating stress, contact fabric, and force fabric tensors with fluctuations in grain velocities and system friction 𝜇. This thesis makes progress toward an end goal of writing down a closed constitutive law for vibrated granular shear flows that could solve for more complex geometries that currently can only be solved with nonlocal models. We gratefully acknowledge funding by the Army Research Office (grants W911NF1510012 and W911NF2220044).