An elasto-plastic finite-element analysis of the metal sheet redrawing process

A methodology for formulating an elasto-plastic finite-element model, based on an updated Lagrangian formulation and the Prandtl-Reuss flow rule, was developed to simulate the redrawing process of axisymmetric sheet metal. An extended r(min) algorithm is proposed to formulate the boundary conditions, such as nodal penetration and separation, alteration of the sliding direction of friction, linearization of strains increments and rotational increments and altered elasto-plastic state of the material. A modified Coulomb's friction law is introduced to describe the alternation between the sliding state and sticking state of faction at the contact interface. The corresponding stiffness equations and solution algorithms are introduced. According to the developed finite-element model, the redrawing process of sheet metal is simulated. Simulation results, such as: (i) the whole deformation history; (ii) the entire loading process history; and (iii) thickness of the workpieces, etc. can be obtained. The simulation clearly demonstrates the efficiency of the model to simulate the redrawing process of sheet metal. This paper has provided a greater understanding of the redrawing process which can lead to improvements in the manufacturing process and in the design of tools. (C) 1999 Elsevier Science S.A. All rights reserved.