题 目：Atomistic Modeling at Experimental Strain Rates and Time Scales
报告人：Harold Park 教授（Boston University）
时 间：2017年5月18日（周四）13:30
地 点：延长校区应用数学和力学所东会议室
摘 要：I will present a new computational approach that couples a recently
developed potential energy surface exploration technique with applied
mechanical loading to study the deformation of atomistic systems at strain
rates that are much slower, i.e. experimentally-relevant, as compared to
classical molecular dynamics simulations, and at time scales on the order
of seconds or longer. I will highlight the capabilities of the new approach
via three distinct examples: (1) Providing new insights into the plasticity
of amorphous solids, with a particular emphasis on how the shear transformation
zone characteristics, which are the amorphous analog to dislocations in crystalline
solids, undergo a transition that is strain-rate and temperature-dependent.
(2) Uncovering new, mechanical force-induced unfolding pathways for the protein
ubiquitin, while also discussing potential differences with experimental data regarding
whether ubiquitin unfolds via an intermediate configuration. (3) Elucidating
strain-rate-dependent transitions in deformation mechanisms and also defect
nucleation stresses in bicrystalline metal nanowires.
