Rigid-viscoplastic dynamic explicit FEA of the ring rolling process

A generalized energy functional describing rigid-viscoplastic dynamic defor mation is newly proposed. The Lagrangian multiplier method and the penalty method are introduced to enforce the incompressibility condition into the f unctional, respectively. The rigid-viscoplastic dynamic explicit finite ele ment equation is established by employing the functional, in which the pena lty method is used to remove the restraint of incompressibility. Then the r ate-type explicit time integration formulation is given by the central diff erence method. A rigid-viscoplastic dynamic explicit finite element code, H -RING, is developed for the analysis of ring rolling. The discussion is mai nly focused on an investigation of the cause and elimination of fishtail de fect in rectangular section ring rolling and the strain distribution in L-s ection profiled ring rolling. The constraint of guide rollers is also intro duced into the calculation. The numerical analysis results are in good agre ement with experiments in terms of geometrical changes and in load variatio n. (C) 1999 Elsevier Science Ltd. All rights reserved.