A Generalization of Plastic Flow Theory With Application to Cyclic Hardening and Softening Phenomena

A generalization of current theories of plasticity is developed. The theory, applicable to arbitrary multiaxial loading histories, requires a strain controlled uniaxial cyclic experiment to specify the material parameters. In its general form, deformation, translation and rotation of the yield surface are permitted. Detailed calculations are carried out for the simple model of combined isotropic and kinematic hardening of an initial Mises yield surface. This model is shown to provide a quantitative representation of the transient uniaxial cyclic hardening process for type 304 stainless steel at elevated temperature. Implementation of the theory in current FEM structures codes should be straightforward.