Visiting Professor, Beihang University, China
Research Professor, Laboratory for Technological Processes, Institute for Problems in Mechanics, Russian Academy of Sciences, Russia

Sergei Alexandrov is a Visiting Professor at Beihang University (Beijing, China) under the program “Recruitment Program for Global Experts” (“1000 Talent Plan”), a Research Professor at the Laboratory for Technological Processes of the Institute for Problems in Mechanics of the Russian Academy of Sciences (Moscow, Russia) and an adjunct faculty member of Ton Duc Thang University (Ho Chi Minh City, Vietnam). He received his Ph.D. in Physics and Mathematics in 1990 and D.Sc. in Physics and Mathematics in 1994. He worked as a Professor at Moscow Aviation Technology Technical University (Russia), a Visiting Scientist at ALCOA Technical Center (USA), GKSS Research Centre (Germany) and Seoul National University (South Korea), and was a Visiting Professor at Aveiro University (Portugal), University of Besancon (France) and Technical University of Malaysia (Malaysia). He is a member of the Russian National Committee on Theoretical and Applied Mechanics. Sergei Alexandrov has published more than 400 papers in journals, books and conference proceedings, including three monographs and around 230 papers in journals indexed in the Web of Science. He has participated in the scientific committee of several international conferences and served as a reviewer in a wide range of international journals. He is on the editorial board of several journals including Continuum Mechanics and Thermodynamics (Springer), Structural Engineering and Mechanics (Technopress) and Symmetry (MDPI). His research areas are plasticity theory, fracture mechanics, and their applications to metal forming and structural mechanics.

Speech Title: Singular solutions in the vicinity of frictional interfaces for material models used in the mechanics of polymers

Aims: This research is aimed at developing the theory of singular solutions for constitutive equations that are suitable for describing the mechanical response of some polymers. The existence of singular solutions allows one to predict the generation of narrow layers with drastically modified properties near frictional interfaces. Such layers are often generated in processing of polymers and metals. The theory proposed in the present paper can be regarded as an extension of the available theory for metals to polymers.

Methods: Asymptotic analysis is used to find the exact singular behavior of the velocity field in the vicinity of frictional interfaces when such behavior exists or to show that solutions are not singular.

Results: In the case of incompressible, pressure-dependent polymers it has been shown that the qualitative behavior of solutions in the vicinity of frictional interfaces is sensitive to the yield criterion adopted. The existence of singular velocity fields has been proven for one of the material models considered. In this case, the exact asymptotic representation of the velocity field near the friction surface has been derived.

Conclusions: For a number of applications it is desirable to choose a material model that leads to singular velocity fields near frictional interfaces. It worthy of note that no direct experiment is capable to distinguish models that lead to the singular velocity fields and models that do not lead to such behavior of the velocity field.