It has long been recognized that many phenomena in the deformation of "hard" matter (crystalline solids) involve processes at many length scales. Canonical examples include the nucleation and motion of dislocations during plastic flow, fracture processes in the vicinity of a crack tip and the processes of grain boundary sliding and migration. Furthermore, it has been noted that key small-scale processes in these phenomena are often highly localized. Therefore, while atomic-level modeling detail is required to accurately capture the smallest features, it is needed only in a relatively localized region. Most of the material may be modelled accurately by continuum methods at considerably lower computational effort. As such, several groups have developed a variety of atomistic/continuum coupling methods over the last two decades or so. The goal of all these methods is nominally to make predictions that are as accurate as a fully atomistic model, but at a fraction of the computational expense.
For many years, the focus of such developments was on an accurate interface between the atomistic and continuum domains, primarily in the static "zero-temperature" limit of deformation phenomena. More recently, the attention has turned to methods that correctly describe such systems at finite temperature, and that allow for the correct transfer of thermal energy between the two modeling regimes.
This talk will include an overview of the generic "coupled" method, explain some of the key features that these methods have, and present some of the challenges they all face. The talk will include a quantitative comparison of the accuracy of some of the more common approaches. Then, attention will be turned to recent atomistic/continuum efforts to correctly describe deformation phenomena at finite temperature.
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