The calculation formulas and the algorithm for the numerical solution of the equations of the theory of elastic-plastic processes in the form of a coplanarity hypothesis when specifying the process of loading by stresses are presented. It is shown that in the case of a constant modulus of the stress deviator (in the absence of hardening on the deformation diagram; passing the yield plateau; loading along an arc of a circle with the center at the origin of the stress space coordinates), the numerical solution becomes indefinite due to the vanishing of the main determinant of the system of calculation equations. When approximating the loading trajectory, for example, by arcs of circles with a displaced center, the solution does not have such an uncertainty.

Sergey L. Subbotin, Doctor of Technical Sciences, Professor, Professor of the Department of Structures and Constructions; e-mail: sbtn@yandex.ru; AuthorID: 174777

Andrey A. Alekseev, Candidate of Technical Sciences, Associate Professor of the Department of Strength of Materials, Theory of Elasticity and Plasticity; e-mail: alexeew@bk.ru; AuthorID: 640538