Multiscale Treatment of Thermo-mechanical Processes in Heterogeneous Solids

The behavior of a microscopic defect in a solid entails processes on vastly diverse scales, ranging  from atomic to macroscopic. Although the course of evolution of the defect is governed principally by large-amplitude irregular (diffusive) atomic movements in the vicinity of the defect ("near" region), the response of the "far" regions of the solid, where atoms merely oscillate with small amplitude about their relatively fixed equilibrium positions, cannot be neglected. For most realistic systems it is impractical to follow the trajectories of all atoms by solving the equations of motion. To reduce the computational burden, one must somehow combine the atomistic description required for the near region with a coarse-grained description that is sufficiently accurate for the far regions. Results of recent work on hybrid atomistic-coarse-graining computational schemes applied to models for crystalline solids and shearing of thin films by our group at University of Nebraska-Lincoln will be presented.

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