A STUDY ON THE EVOLUTION OF SUBSEQUENT YIELD SURFACES WITH FINITE DEFORMATION

The subsequent yield surfaces after a finite deformation show expansion or contraction, translation and distortion. Based on the slip mechanism, a plastic constitutive model for polycrystalline metals with a finite deformation is proposed. A mixed hardening model is developed in the present paper to describe the isotropic hardening, kinematic hardening, distortional hardening, positive or negative cross-effect and Bauschinger effect characterized by the evolution of subsequent yield surfaces. Numerical simulations of the evolution of yield surfaces are performed under tension and pure torsion at various levels of straining for two kinds of work hardening aluminum alloys (Al6061-T6511 and annealed 1100Al). The results show that the agreement between the predictions and experiments is quite satisfactory.