ON THE NECESSITY OF THE CONSTITUTIVE EQUATIONS FOR THE PLASTIC SPIN
论塑性旋率本构方程的必要性

In the theory of finite elasto-plasticity, the constitutive relation is usually in the form of rate type. Hence the decomposition of strain rate based on the concept of intermediate configuration has become very popular, and among others, works developed by E. H. Lee et al. and Y. F. Dafalias et al. may be considered to be the most influential. Nevertheless, it is shown in this paper that, at least for some special cases, certain relation that the substruc-tural spin should satisfy can be derived. Thus, it becomes unnecessary to give the constitutive equation for the plastic spin. Clearly, the present theory is different from that either by Dafalias or by E. H. Lee. In order to determine the substructural spin, the former has to give the constitutive equaiton for the plastic spin, and the latter has to make certain implied assumptions on the decomposition of strain rate. It is believed that the present result may be used to pro-vide a new approach in the constitutive theory of finite plasticity.