elasticity, creep, plasticity.

In the framework of the theory of small deformations the paper presents the solution of a boundary value problem about a deformation process of the material with elastic, viscous and plastic properties. The material is placed between two spherical surfaces and deformed under the action of uniform pressure changing with the times. Rheological effects are taken into account at the stage of deformation, which precedes the plastic flow. Reversible and irreversible deformations, stresses, and displacements are calculated. The regularity of motion of the elastoplastic boundary in the layer is established.

Galimzyanova Kseniya Nailevna e-mail: gal-ksyusha@ya.ru, Postgraduate Student, Institute of Automation and Control Processes of FEB RAS, Vladivostok, Russia.

Kovtanyuk Larisa Valentinovna, e-mail: lk@iacp.dvo.ru, Dr. Sci. Phys. & Math., Head of the Laboratory of Irreversible Deformation Mechanics, Institute of Automation and Control Processes of FEB RAS, Vladivostok, Russia.

Panchenko Galina Leonidovna e-mail: panchenko.21@yandex.ru, Candidate of Phys. & Math.; Senior Researcher, Institute of Machinery and Metallurgy of FEB RAS, Komsomolsk-on-Amur, Russia; Assoc. Professor, Vladivostok State University of Economics and Service, Vladivostok, Russia.