Three-level constitutive model describing behavior of polycrystals with monotonic and non-monotonic strain diagrams

Abstract

A three-level constitutive model that describes from concurrent positions the behavior of materials with monotonic and non-monotonic strain diagrams is considered. An effect of the anisotropy and strengthening coefficients of the crystal, the average value of the grain diameter and distribution density of structural defects on the macroscopic behavior of the polycrystal is established. Thereto, three postulates are used: averaged connections, extremum of discrepancy between the macroscopic measures and their microscopic analogues, and orthogonality of stress and strain fluctuations. Based on the constructed system of governing equations, the specific effects of the structural characteristics of the polycrystal on macroscopic strain diagrams and elasticity constants are studied.