Concept of Plastic Gas and Model Medium for Dilatable Isotropic Materials

Abstract

The approach to the study of plastic deformation processes of dilatable isotropic materials from the viewpoint of the concept of plastic gas is considered. A definition of the dilatation medium, which is called a plastic gas, is presented. The loading function and its possible types are given. The dependences of the porosity coefficient on pressure are established and the areas of its variation are determined. Relationships between mean stress, density, and compaction coefficient are ascertained. Using the hypothesis of coaxiality of stress deviators and strain rates, the relationships between stresses and strain rates are determined. For the case of a plane deformation of a dilatable medium that obeys the Coulomb plasticity condition, formulas are obtained for calculating the components of the stress tensor, allowing analysis of the stress-strain state, i.e., performing a full study of the process.