Wave propagation in a multiscale model which directly combines MD and FE (Xiong, Chen, Zhang, McDowell and Chen, 2014)

Wave propagation in our concurrent atomistic-continuum model  based on an atomistic field formalism (Xiong, Chen, Zhang, McDowell and Chen, 2014)

After two decades of extensive research efforts, there is still a need for a generally successful multiscale method that can simultaneously allow full sets of phonon waves and a variety of defects to naturally pass through the atomistic-continuum interfaces. This is one of the most formidable obstacles in linking atomistic to continuum for multiscale modeling of materials.

In our group, working together with our collaborators, we develop a concurrent atomistic-continuum (CAC) methodology that promises to meet this challenge. The framework of CAC combines a multiscale formulation of balance equations which link atomistic to continuum through statistical mechanics, and a generalized finite element method. Simulation results show that CAC preserves the atomistic nature and enables the predictions of progressive failure and transport behavior of materials from collections of atoms to micron-sized specimens. The unique feature of CAC was demonstrated through the passage of dispersive phonon waves (movies shown above), and the transmission of dislocations as well as stacking faults (figures shown below) across the atomistic/continuum interfaces.