Title: A Brief Survey of Atomistic-to-Continuum (AtC) Coupling

Speaker: Michael Parks, NECIS Student

Date/Time: Wednesday, June 14, 2006, 3:00 – 4:00 pm (MDT) videoconferenced

Location: Bldg. 980/95 videoconferenced to 940 Auditorium Sandia/CA

Brief Abstract: Many important physical phenomena, such as deformation and failure, are inherently multiscale processes that cannot always be modeled with a traditional finite element analysis. Typically this inability is either because the scale of the domain is small enough that the continuum approximation becomes dubious, or because complex atomistic processes affect macroscopic behavior. In these situations one must resort to an atomistic description to resolve the underlying physics. Unfortunately, fully atomistic simulations of most domains of interest are computationally infeasible, so multiscale modeling methods coupling atomistic and continuum simulations are considered. Atomistic-to-Continuum (AtC) coupling enables a continuum calculation to be performed over the majority of a domain of interest while limiting the more expensive atomistic simulation to a subset of the domain. Unfortunately, combining atomistic and continuum calculations is challenging because the former is based on individual non-local force interactions between atoms while continuum calculations deal with bulk properties of matter that represent the averaged behavior of huge numbers of atoms. This requires methods to couple across length and time scales spanning many orders of magnitude---from the atomic to the macroscopic.

I will provide a brief overview of methods for coupling atomistic and continuum models, and demonstrate the behavior of several existing AtC methods on simple model problems. I'll also discuss some of the difficulties associated with a mathematical analysis of AtC methods.

CSRI POC: Scott Collis, (505) 284-1123