An experimental study of incremental response functions in the totally plastic region

Abstract

Experimental data are obtained from thin-walled tubes of annealed polycrystalline aluminum subjected to combined tension-torsion loadings. These data reveal that the plastic deformation in the totally plastic region can be described in terms of a path independent loading function and incremental response functions according to which the component of the plastic strain increment vector is decomposed into two parts: one is due to the expansion of the loading surface and the other is due to the change of the corresponding component of the stress vector and vanishes when the directions of stress and strain vectors coincide.