About a possible criterion of limiting plasticity of structural metal alloys

Abstract
When using plastic metal alloys in constructions of shell casings of explosion-resistant chambers and when testing material samples, variants of plastic flows with uniaxial extension (extension of bar or radial extension of ring) and biaxial extension (extension of element of plate, cylindrical or spherical shell) take place. The mentioned types of plastic flow are considered in the work, where, with the supposition on continuity and incompressibility of material, the relation of lateral relative deformation in the direction of element thickness regarding to the basic (active) deformation (i.e. coefficient of lateral deformation) is calculated depending on its value. It is revealed in the work that the ultimate plasticity of some metal alloys (steels 20, 35, 12Kh18N10T, aluminum alloy AMg6), for which the experimental data are available on the considered types of plastic flow, has inverse correlation with the mentioned coefficient of lateral deformation. This coefficient can be used as a criterion for evaluation of destructive relative plastic deformations of constructions and their safety factors during experimental determination of line of its regression at ultimate (destructive) deformations in the conditions of loading of model samples, which are maximum close to the conditions of operation of full-scale constructions.