Discrete dislocation modelling of submicron indentation

Indentation of a planar single crystal by a circular rigid indenter is analyzed using discrete dislocation plasticity. The crystal has three slip systems and is initially dislocation-free, but edge dislocations can nucleate from point sources inside the crystal. The lattice resistance to dislocation motion, the interaction with point obstacles and dislocation annihilation are incorporated through a set of constitutive rules. Indentation is displacement driven and at each stage of the loading history, a boundary-value problem is solved for the evolution of the indentation pressure and the contact size. Preliminary results are presented for various values of the density of dislocation sources.