Modeling Dislocation Density Evolution During Microparticle Impacts

A continuum-scale material model that is applicable over a wide range of loading conditions will be presented. The model is comprised of three coupled ordinary differential equations: a kinetic equation, which relates the strain-rate to the stress, mobile and immobile dislocation densities, mass density, and temperature, and two equations describing the evolution of the mobile and immobile (network, forest) dislocation densities. The dislocation density evolution equations account for a variety of known storage, dynamic recovery, and dislocation multiplication mechanisms in face-centered cubic metals. The model will then be applied to model copper-on- copper microparticle impacts with impact velocities ranging from ~100-1100 m/s. Simulated results are compared to experimental data reported in literature to validate the model.