rotating cylinder, hollow cylinder, small strain, viscoplasticity, creep, plain strain, generalized plain strain.

Deformation of a rotating hollow cylinder made of material with elastic, plastic and creep properties is studied. Cylinders with fixed and free ends are considered. It is assumed that strains in cylinder are small. Angular velocity firstly increases gradually from zero to specified maximum value. After that, it is maintained constant for some time interval. Finally, angular velocity decreases gradually until the cylinder stands still. It is supposed that the rotation speed varies slowly with time, so angular acceleration may be neglected. Initially, irreversible strains are caused only by the creep of the material but at a certain value of angular velocity the plastic region appears and develops in the cylinder. After that, an unloading elastoplastic boundary arises. The region of plastic flow decreases with the advancement of this boundary surface in media. Elasticplastic boundaries are the place where the mechanism of production of irreversible deformations changes. The constitutive system of equations is solved by using the finite difference method. The results of numerical calculations including stress relaxation after stand-still of a cylinder are presented and analyzed.

Firsov Sergey Viktorovich, Junior Researcher, Institute of machinery and metallurgy of Far Eastern Branch oftheRAS, Komsomolsk-on-Amur, Russia.

Prokudin Alexander Nikolaevich, Candidate of Engineering Sciences, Leading Researcher, Institute of machinery and metallurgy of Far Eastern Branch oftheRAS, Komsomolsk-on-Amur, Russia.