  This work presents an open source, dislocation density based crystal
plasticity modeling framework, $\rho$-CP. A Kocks-type thermally activated flow
is used for accounting for the temperature and strain rate effects on the
crystallographic shearing rate. Slip system-level mobile and immobile
dislocation densities, as well slip system-level backstress, are used as
internal state variables for representing the substructure evolution during
plastic deformation. A fully implicit numerical integration scheme is presented
for the time integration of the finite deformation plasticity model. The
framework is implemented and integrated with the open source finite element
solver, Multiphysics Object-Oriented Simulation Environment (MOOSE). Example
applications of the model are demonstrated for predicting the anisotropic
mechanical response of single and polycrystalline hcp magnesium, strain rate
effects and cyclic deformation of polycrystalline fcc OFHC copper, and
temperature and strain rate effects on the thermo-mechanical deformation of
polycrystalline bcc tantanlum. Simulations of realistic Voronoi-tessellated
microstructures as well as Electron Back Scatter Diffraction (EBSD)
microstructures are demonstrated to highlight the model's ability to predict
large deformation and misorientation development during plastic deformation.
