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   COLLOQUIUM OF THE LABORATORY FOR COMPUTER DESIGN OF MATERIALS        
        Institute for Computational Sciences and Informatics	
                           (CSI 898-Sec 001) 
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          How things bend and break: theory and simulation of 
                      deformation and fracture

                        Robin L. B. Selinger
        Physics Department, Catholic University, Washington, DC

Using a combination of classical atomistic simulation and statistical
physics models, I'll explore a variety of problems in basic materials
science involving the dynamics and patterning of dislocations and cracks. 
The questions I'll address include:

- Why does a dislocation develop nontrivial structure even in a simple
geometry, e.g. when a straight dislocation is attracted toward a parallel
free surface? 

- How and why do dislocations form ordered patterns, or shear bands, when
a metal is deformed monotonically in shear? 

- When a planar crack propagates at high speed through a disordered
medium, how does the crack-front roughen into a self-affine structure
over time? 

- When a fast-moving crack in a uniform solid runs into an obstacle, what 
are the disturbances that propagate laterally along the crack front? 

I'll also discuss work presently underway on understanding the
brittle-ductile transition--a problem involving both dislocations and
cracks--and how statistical physicists and materials scientists approach
this problem with completely different points of view. 

                        Monday , February 28, 2000
                                  4:30 pm
                        Room 206, Science & Tech. I

Refreshments will be served.
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Find the schedule at http://csi.gmu.edu/lcdm/seminar/schedule.html