A more sophisticated hardening law for the theory of plasticity

A new hardening law is introduced into the classical incremental theory of plasticity for initially isotropic solids allowing us not only to rigidly translate, transversely isotropically deform and rotate, but also to distort the yield surface. The law, on the whole, can satisfactorily describe modifications of the surface experimentally obtained by other authors in complex biaxial tension-torsion Loading of thin-walled tubular specimens of pure aluminum.