Non-Associated Plastic Flow
John Bassani (University of Pennsylvania)
From Atomistics to Reality: Spanning Scales in Simulations and Experiments Symposium A
Mon 10:45 - 12:15
CIT 165
The structure of classical plasticity theory for crystalline materials is generally assumed to be associative in the sense that the flow potential is taken to be the yield function. Ample experimental evidence now exists that non-associated flow more appropriately characterizes dislocation glide, but not until atomistic simulations became sufficiently refined have we been in a position to rigorously address the issue. Atomistic simulations are used to construct multislip models for single crystals, and polycrystal constitutive relations are derived using simple homogenization techniques. Key features of experiments on single and polycrystals are in accord with the models derived from multiscale analyses. At all levels, non-associated flow persists, and this is shown to significantly affect macroscopic deformations, in particular strain localization. In addition, intermittent bursts of strain are predicted to arise under certain deformation histories as a consequence of non-associated flow.