A Combined Kinematic--Isotropic Hardening Theory for Porous Inelasticity of Ductile Metals

A general treatment of multiaxial inelastic deformation for arbitrarily large strain necessitates consideration of effects of material porosity and its evolution, combined kinematic--isotropic hardening, dislocation substructure stress-state effects and textural anisotropy, rate- and temperature-dependence, void anisotropy, and failure criteria, among other things. The full set of three invariants of the stress (overstress) tensor is essential for a satisfactory first-order description of these effects. A framework is set forth that is sufficiently general to include arbitrary void growth laws and various state variable inelasticity theories. The framework is applied, within the context of rate-independent plasticity, to predict evolution of void growth during tensile loading of pressurized, circumferentially notched specimens using two different void growth models.