THE EXTENDED ELASTOPLASTIC CONSTITUTIVE EQUATION WITH TANGENTIAL STRESS RATE EFFECT

The extension of the elastoplastic constitutive equation so as to desc ribe the plastic stretching due to the stress rate component tangentia l to the yield or loading surface has been one of the most pressing pr oblems in the elastoplasticity. To this aim, various models have been proposed in the past. However, a pertinent model applicable to a gener al loading process has not previously been proposed. In this article, the elastoplastic constitutive equation extended so as to describe a p lastic stretching due to a stress rate component tangential to a yield or loading surface is formulated keeping a single and smooth yield su rface. It would be a pertinent one which fulfills the mechanical requi rements for elastoplastic constitutive equation and which is applicabl e to an arbitrary loading process. Based on this equation, a constitut ive equation of metals with the isotropic-kinematic hardening is formu lated.