Youping Chen Colloquium: Concurrent Atomistic-Continuum Modeling and Simulation of Transport Processes in Crystalline Materials

Title: Concurrent Atomistic-Continuum Modeling and Simulation of Transport Processes in Crystalline Materials

ABSTRACT
In this talk we present a concurrent atomistic-continuum (CAC) method for modeling and simulation of transport processes in crystalline materials. The CAC formulation extends the Irving-Kirkwood procedure for deriving transport equations and fluxes for homogenized molecular systems to that for polyatomic crystalline materials by employing a concurrent two-level structural description of crystals. A multiscale representation of conservation laws is formulated that holds instantaneously, as a direct consequence of Newton’s second law, using the mathematical theory of generalized functions. Finite element (FE) solutions to the conservation equations, as well as fluxes and temperature in the FE representation, are introduced, followed by numerical examples of atomic-scale structures of interfaces, dynamics of fracture and dislocations, and phonon transport in multiscale structured materials. In addition to providing a methodology for concurrent multiscale simulation of transport processes under a single theoretical framework, the CAC formulation can also be used to compute fluxes (stress and heat flux) in atomistic and coarse-grained atomistic simulations.

Biography
Dr. Youping Chen is an Associate Professor in the Department of Mechanical & Aerospace Engineering at the University of Florida. His research focuses on linking and concurrently coupling atomistic and continuum description of transport processes. Her theoretical research leads to the development of the CAC (concurrent atomistic-continuum) method for mesoscale simulations of defect dynamics and phonon transport. She completed her Ph.D. at the Georgia Washington University in 2003, where she reformulated A. C. Eringen’s Micromorphic theory from the atomistics.  She was a recipient of DARPA Young Faculty Award in 2010 and DOE Early Career Award in 2011.