Subsequent yield surface probed from its current center

To formulate the constitutive equations for modern plasticity, the subsequent yield surfaces after tension and/or torsion preloading have been examined for an initially isotropic material of SUS304, using a 50 mu m/m offset strain definition of yield. The most important concept in this paper is that the subsequent yield surface should be probed from the current center. As a result, all the surfaces are described by the ellipse even though they are deformed, translated, or rotated by the history of loading. The anisotropic coefficient tensor component proposed in this paper allows an accurate depiction of the surface. (C) 1997 Published by Elsevier Science Ltd.