A theoretical, numerical, and experimental investigation of plastic wrinkling of circular two-layer sheet metal in the deep drawing

In this paper, the wrinkling of two-layer (aluminum-stainless steel) sheets in the deep drawing process, is investigated through an analytical method, numerical simulations, and experiments. In a deep drawing process, wrinkling can always be eliminated with an increase in the blank holder force (BHF). Thus, the aim of this study is to obtain the minimum required BHF to prevent wrinkling. In the analytical model, energy method is used to predict the wrinkling. Also, FE simulations were performed to study the effect of forming parameters on wrinkling. Experiments have been conducted to verify the analytical model and FE simulations. The effects of parameters such as the material properties of aluminum layer and lay-up on BHF and forming force are investigated. Results demonstrate that the optimum BHF is dependent on the blank geometry, material properties and lay-up. It is shown that BHF is greater when aluminum is in contact with the punch. Results show a good agreement between analytical, FE, and experimental results. (C) 2010 Elsevier B.V. All rights reserved.