A dislocation-based multi-rate single crystal plasticity model

The goal of this work is to formulate a constitutive model for the deformation of metallic single crystals over a wide range of strain rates, which is integral to computing reliable stress states of metallic polycrystals under shock loading. An elastic-viscoplastic, slip-based single crystal model that accounts for crystallographic orientation, temperature, and strain rate dependence has been formulated based on dislocation dynamics simulations and existing experimental data. The plastic model transitions from the low-rate, thermally-activated regime, to the high-rate, drag-dominated regime, by use of a distribution of dislocation velocities including kinetic effects. It has been compared favorably with experimental and computational results of copper. The transition to drag-dominated dislocation motion is predicted rather than empirically fit to experimental data.

► A dislocation-based single cyrstal plasticity model is formulated.
► The model operates over a range of strain rates: 102 upwards.
► A transition between low-rate and high-rate dislocation motion is predicted.
► The model compares to copper experimental and simulation results.