李少凡教授学术报告.doc

李少凡教授学术报告
题目: A Multiscale Dislocation Pattern Dynamics
---Towards an atomistic-informed crystal plasticity
报告人: 李少凡教授 University of California-Berkeley
时间: 7月7日 10:00
地点: 江宁校区乐学楼1116
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河海大学力学与材料学院计算力学研究所
Abstract:
Dislocations in a deformed crystal tend to aggregate into various dense formations separated by relatively dislocation free regions. These dense formations are called dislocation patterns that underlie most important crystal plasticity features such as work hardening and strain localization. In this work, we show that the previously developed multiscale crystal defect dynamics (MCDD) method (Li et al. (2015) Philosophical Magazine, 94,1414-1450. and Lyu and Li, (2017) Journal of Mechanics and Physics of Solids, 107, 379-410.) is actually a discrete dislocation pattern dynamics, in which we link the early pattern of the dislocation distribution, or the microstructure of crystal defect in general, with that of original crystal lattices as part of material genome.
The main developments of present work are: (1) Using the dislocation dynamics invariants and scaling laws, we demonstrated that the multiscale crystal defect dynamics is in fact a multiscale dislocation pattern dynamics; (2) The multiscale dislocation pattern dynamics may lead to an atomistically-informed crystal plasticity theory, and (3) It is shown that cyclic plastic responses of FCC cr