报告主题：Gradient Continuum Nanomechanics: Applications to Nanoelasticity, Nanoplasticity and Nanodifussion
报 告 人：E.A.Aifantis（Aristotle University of Thessaloniki, Greece)
报告时间：2014年12月19日（周五)9:30
报告地点：延长校区应用数学和力学研究所
主办部门：理学院力学所
报告摘要: Nobel laureate Richard Smalley's quotation "The Laws of Continuum Mechanics are amazingly robust for treating even intrinsically discrete objects only a few atoms in diameter" appears to be applicable for a wide range of nanoscale materials and processes involving elastic and plastic deformations, as well as diffusion processes. Robust nanoelasticity, nanoplasticity and diffusion models can result by incorporating an extra Laplacian term in the standard equation of elasticity, plasticity and diffusion. As a result strain/stress singularities at dislocation lines and crack tips can be eliminated, incipient and intermittent stress-strain curves can be effectively interpreted, and size-dependent phase diagrams may be constructed. The examples of adiabatic shear banding and size-dependent spinodal gaps are discussed. When evolution equations are not available to describe the statistical distribution of the experimentally recorded deformation characteristics (stress drops, strain bursts), it is shown that Tsallis' non-extensive thermodynamics can be used to fit the observed power-law behavior that cannot be modeled by using conventional Boltzmann-Gibbs-Shannon thermodynamics.