Quasicontinuum simulation of brittle cracking in single-crystal material
T. L. Xu, J. H. Fan, R. Stewart, X. Zheng and A. Yao
Crystal Research and Technology, 52, 1600247 (2017).


Multiscale modeling has received unprecedented attention in various fields recently, with bottom-up and top-down transitions between neighboring subscales considered as important strategies for understanding defect initiation and evolution on the atomistic, nano, and submicron scales. The multiscale approach to the simultaneous modeling of multiple scales has been applied to the strong coupling between variable groups of different scales. In addition, the quasi-continuum (QC) method uses non-local and local repatom regions for seamless bridging between the atomic and continuum regions. With specific application to the classical plate-with-a-hole problem, a quantitative evaluation of the precision of the QC model was undertaken in this study. The analytical displacement field was solved using the specific regions as the atomic displacement comparison criteria. A certain amount of "ghost" interference was observed at the interface between the atomic and continuum mediums, and the crystal orientation effect of the alpha-Fe crack tip atoms was used to analyze the dislocation emission, twinning, void nucleation, and crack propagation in specific grains. The defect evolution under tension loading was also analyzed with the aid of a typical crystal, and the strain-force response relationship was used to elucidate the processes of crack initiation, brittle cracking, blunting, void nucleation, and complete rupture.