Emission of elastic waves from a dislocation in a 2-D discrete lattice

Abstract

A dislocation moving in a lattice emits elastic waves, as it accelerates and decelerates due to the lattice periodicity. In this work, simulations of this process in a 2-D discrete square lattice are presented. Under a small applied stress, the dislocation motion from an unstable position to the next stable position is accompanied by emission of dipolar waves, followed by quadrupolar emission when it oscillates around the stable position. When the applied stress is larger than 70% of the Peierls stress, the dislocation overcomes the Peierls hills, and after moving a few atomic distances it achieves a steady motion with alternating forward motion and “hesitation” or oscillation, accompanied by radiations of dipolar and quadrupolar waves.