The paper analyzes the properties of the constitutive relations of the theory of plasticity for a continuum, which plastic properties depend on the type of stress state. The plasticity condition
Within a method of small parametre the field of stresses of heavy tubing cylindrical pipes is investigated at modelling of a material by the incompressible elasticis viscous-plastic environment. The estimation of influence on size of a plastic zone physicomechanical design parametres is given.
