Experimental results aimed at establishing the relationship existing between plastic instantaneous and creep strains are reported. They are chiefly tensile at constant strain rates and tensile or tensile-torsion creep experiments. Recovery and hardening are also measured. It is shown that two types of viscous behavior may occur according to whether the loading path is an active loading or an unloading. The features of these two types of viscoplastic behavior are such that they can be modeled with the same plastic state equation using a single internal variable. But according to a criterion based on internal variables, the single internal variable of the plastic state equation may split into the sum of an isotropic and a kinematical variable with small strain hardening (case of large viscoplastic strains) or remain a single kinematical variable with very high hardening (case of unloadings). The bases of the model are described.

This content is only available via PDF.
You do not currently have access to this content.