  Cross-slip is a thermally activated process by which screw dislocation
changes its glide plane to another slip plane sharing the same Burgers vector.
The rate at which this process happens is determined by a Boltzmann type
expression that is a function of the screw segment length and the stress acting
on the dislocation. In continuum dislocation dynamics (CDD), the information
regarding the length of the screw dislocation segment and local stress state on
dislocations are lost due to the coarse-grained representation of the density.
In this work, a data driven approach to characterize the lost information by
analyzing the discrete dislocation configurations is proposed to enable
cross-slip modeling in the CDD framework in terms of the coarse-grained
dislocation density and stress fields. The analysis showed that the screw
segment length follows an exponential distribution, and the stress
fluctuations, defined as the difference between the stress on the dislocations
and the mean field stress in CDD, follows a Lorentzian distribution. A novel
approach for cross slip implementation in CDD employing the screw segment
length and stress fluctuation statistics was proposed and rigorously tested by
comparing the CDD cross-slip rates with discrete dislocation dynamics (DDD)
rates. This approach has been applied in conjunction with three cross-slip
models used in DDD simulations differing mainly in the functional form of cross
slip activation energy. It was found that different cross-slip activation
energy formulations yielded different cross-slip rates, yet the effect on
mechanical stress-strain response and dislocation density evolution was minimal
for the [001] type loading.
