(LNM-10月13日10:00)Internal Lengths & Times in Chemomechanics:Applications in Technology, Geology and Biology
报告题目：Internal Lengths & Times in Chemomechanics:Applications in Technology, Geology and Biology
报告人: Prof. E.C. Aifantis
Aristotle University of Thessaloniki, Michigan Technological University,
Beijing University of Civil Engineering and Architecture, ITMO University, Togliatti State University
The lecture outlines a number of key concepts and ideas that have not been explored so far in the area of chemomechanics or mechanochemistry, i.e. at the meeting point of mechanics and chemistry. An attempt is made to cast these ideas into an initial mathematical framework for describing a variety of coupled chemomechanical phenomena occurring in engineering materials, in the earth crust and in the human body.
The new viewpoint advanced here is that in order to capture and control chemomechanical instabilities across the scale and material spectrum we need to resort to internal length and time scales associated with the evolution of the system. One convenient way to account for this is through the introduction of second spatial (Laplacian) and time (inertia) derivatives of the pertinent mechanical, chemistry and structural variables in the constitutive equations describing the evolution of the chemomechanical system at hand.
When differential equations are not available for describing material behavior, Tsallis non-extensive thermodynamic formulation is employed to characterize statistical properties. The extension of the approach to consider fractional derivatives and fractal media is explored.
Examples to discuss include stress corrosion cracking, phase separation in lithium-ion electrodes, and fracture of microcrystals with five-fold symmetry used as catalysts. An adaptation of the approach to consider chemomechanical damage of brain tissue and neural cell modeling is described.
Elias Aifantis is a Professor of Mechanics at the Aristotle University and has been a Distinguished Research Professor of Engineering at Michigan Tech until 2010. Prior to that he held faculty appointments at the University of Minnesota and the University of Illinois at Urbana-Champaign. He has received his Diploma on Mining & Metallurgy in 1973 from the NTU-Athens, and his PhD on Chemical Engineering and Materials Science from the University of Minnesota in 1975. He has published ~550 articles in journal and proceedings [citations: ~ 8505/ISI, ~8680/SCOPUS; h-index: 47/ISI, 46/SCOPUS]. He is included in the Thomson Reuters list of Highly Cited Researchers in Engineering. He quoted the terms "material instabilities", "dislocation patterning", "chemomechanics", "nanomechanics" and helped promoting the scientific disciplines know today as "gradient elasticity" and "gradient plasticity", through his early papers on these subjects in 1984 and 1992 respectively.