报告一：Nnaomaterials & Nanomechanics
报告人：Elias C. Aifantis
报告内容摘要：
After a brier review of some pioneering experimental observations by the author and his MTU colleagues in the mid 90’s on nanocrystalline (nc) and ultrafine-grained (ufg) polycrystals, an extended continuum mechanics framework for interpreting these observations is sketched. It accounts for “bulk-surface” interactions in the form of extra gradient terms that enter in the balance laws and/or the evolution equations of the relevant constitutive variables that govern behavior at the nanoscale. The effectiveness of the approach is shown by considering certain benchmark problems for nanoelasticity, nanoplasticity and nanodiffusion for which standard continuum mechanics theory fails to model the observed behavior. Its implications to interpreting inverse Hall-petch behavior and size-dependent stress-strain curves for nanopolycrystals with varying grain size are also discussed.
报告人简介：
Professor Elias C. Aifantis is a renowned scientist, with many pioneering works in mechanics. He received PhD degree from Univ. of Minnesota at 1975. His research interests cover a broad area, including diffusion and environmental, stress corrosion cracking, flow through porous media and soil/rock mechanics, phase transitions and interfaces, micro/nanomechanics of elasticity, plasticity and fracture, material instabilities – dislocation patterning/shear banding/damage localization, gradient elasticity/plasticity and size effects, novel and nanostructured materials. He has published over 450 papers on these subjects as articles in scientific journals and chapters in books, with about 5300 citations and H-factor 38.
报告二：Capturing Deformation at the Nano and Micron Scales
报告人：Katerina E. Aifantis
报告内容摘要：
In order to explicitly account for the effect of interfaces in the micron and nano scales, two gradient plasticity frameworks have been proposed: (i) At the micron scale interfaces oppose dislocation motion and therefore the interface is taken to act as a surface of discontinuity for the plastic strain gradient and a separate interface energy parameter is assigned to internal surfaces. (ii) At the nanoscale due to the higher surface to volume ratio a finite interface thickness must be accounted for and therefore interfaces are treated as a separate phase. Both models are in agreement with experimental evidence regarding deformation in the micron and nanoscale.
报告人简介：
Professor Katerina E. Aifantis received her PhD degree from the University of Groningen in 2005, and became the youngest recipient of the European Research Council Starting Grants in 2008. Her research interests range from the mechanical properties of nanocrystals to the electrical stimulation of cells, and Li battery damage.
时 间：11月19日（周五）下午2:00-4:00
地 点：力学楼434会议室
主持人：唐少强（教授）