This is a part of GT MAP activities. There will be light refreshments through out the event. This seminar\ will be held at Skiles 006.
A couple of members of Prof. McDowelli's group will present their research
3:00 PM - 3:45PM Prof. David McDowell will give a talk on
" Multiscale Crystal Plasticity Modeling for Metals".
3:45PM -- 4:00PM Break with Discussions
4:00PM - 4:25PM Shuozhi Xu (PhD Candidate) will give a second talk on
" Algorithms and Implementation for the Concurrent Atomistic-Continuum Method"
4:25PM - 5PM Discussion of open problems stemming from the presentations.
Prof. McDowell's Talk Title] Multiscale Crystal Plasticity Modeling for Metals
Crystal plasticity modeling is useful for considering the influence of anisotropy of elastic and plastic deformation on local and global responses in crystals and polycrystals. Modern crystal plasticity has numerous manifestations, including bottom-up models based on adaptive quasi-continuum and concurrent atomistic-continuum methods in addition to discrete dislocation dynamics and continuum crystal plasticity. Some key gaps in mesoscale crystal plasticity models will be discussed, including interface slip transfer, grain subdivision in large deformation, shock wave propagation in heterogeneous polycrystals, and dislocation dynamics with explicit treatment of waves. Given the mesoscopic character of these phenomena, contrasts are drawn between bottom-up (e.g., atomistic and discrete dislocation simulations and in situ experimental observations) and top-down (e.g., experimental) information in assembling mesoscale constitutive relations and informing their parameters.
Shuozhi Xu's Talk Title] Algorithms and Implementation for the Concurrent Atomistic-Continuum Method
Unlike many other multiscale methods, the concurrent atomistic-continuum (CAC) method admits the migration of dislocations and intrinsic stacking faults through a lattice while employing an underlying interatomic potential as the only constitutive relation. Here, we build algorithms and develop a new CAC code which runs in parallel using MPI with a domain decomposition algorithm. New features of the code include, but are not limited to: (i) both dynamic and quasistatic CAC simulations are available, (ii) mesh refinement schemes for both dynamic fracture and curved dislocation migration are implemented, and (iii) integration points in individual finite elements are shared among multiple processors to minimize the amount of data communication. The CAC program is then employed to study a series of metal plasticity problems in which both dislocation core effects at the nanoscale and the long range stress field of dislocations at the submicron scales are preserved. Applications using the new code include dislocation multiplication from Frank-Read sources, dislocation/void interactions, and dislocation/grain boundary interactions.
Regents’ Professor and Carter N. Paden, Jr. Distinguished Chair in Metals Processing, Dave McDowell joined Georgia Tech in 1983 and holds appointments in both the GWW School of Mechanical Engineering and the School of Materials Science and Engineering. He served as Director of the Mechanical Properties Research Laboratory from 1992-2012. In August 2012 he was named Founding Director of the Institute for Materials (IMat), a Georgia Tech interdisciplinary research institute charged with cultivating a campus-wide materials innovation ecosystem for research and education. IMat is involved in regional and national leadership roles for the Materials Genome Initiative (see http://www.materials.gatech.edu).