A Framework for Continuum-Atomistic Simulations of Crack Tip Plasticity

Multiscale simulations of crack tip plasticity suffer from one significant limitation- as these simulations progress, large regions of the simulation domain areconverted from continuum to atomistics to accommodate the evolution ofdislocations. We will describe a new continuum-atomistic framework formodeling dislocations which allows one to retain atomic resolution in the nearcore region, without significantly increasing the number of degrees of freedom inthe system. The framework combines the Bridging Domain Method (BDM) withthe eXtended Finite Element Method (XFEM). The XFEM-BDM frameworkallows the coarse-graining of both regions where the atomistic displacements arehomogeneous and where they are discontinuous by replacing large portions of theatomistic domain along the glide planes and crack by XFEM approximations.The framework will be compared to several direct numerical simulations and itsadvantages and limitations will be discussed.