Sheet-forming process characterization by static-explicit anisotropic elastic-plastic finite-element simulation

Abstract

The Static-explicit finite-element simulation code has been proven to be a robust tool for prediction in highly non-linear sheet-forming processes. This code has been developed employing a rate-type formulation, based on non-linear shell theory, non-linear contact friction theory and an anisotropic elastic-plastic constitutive equation. The Euler method has been employed for the time integration of the equation of motion under the quasi-static condition. The C 0 continuity shell finite-element model has been proven to be an efficient model for large-scale finite-element computation. The sheet-forming process involves the highly non-linear phenomenon of a complicated mechanical system. The coupling of the contact boundary condition and the material properties causes instability phenomena, such as localization and wrinkling. These instability phenomena are studied using a “Forming Process Map”, which characterize thinning and draw-in deformation processes, and also the phase diagram. The investigations are carried out in the case of square-cup deep drawing adopting NUMISHEET93 materials, such as mild steel and aluminum alloy.