An improvement of the Prandtl-Reuss theory and the hybrid / mixed vari-stiffness method of finite element analysis

The common Prandtl-Reuss theory has been improved in this paper. A quasi-flow law of the isotropic hardening Mises materials has been proposed as well, on the basis of which, an efficient iterative algorithm of finite element analysis, hybrid / mixed vari-stiffness method, has been obtained. The numerical examples calculated by the plane stress / strain element model are given. Compared with the common initial stress method, the hybrid / mixed vari-stiffness method shows its advantages in the convergent speed, calculating accuracy and treatment scheme of the incompressibility of materials.