Prediction of forming limit diagram of AA7075-O aluminum alloy sheet based on modified M-K model

Abstract

To accurately predict the forming limit diagram of AA7075-O aluminum alloy sheet,a modified M-K model was put forward based on the ductile fracture criterion and the traditional M-K model. By using the method which combined the uniaxial tension simulation with experiment,the history of stress-strain of the dangerous element was substituted into the C-L ductile fracture criterion which was implemented into Abaqus / Explicit to get the material constant. Based on the forming limit data obtained by the uniaxial tensile,the initial thickness imperfection in the modified M-K model was obtained by the method which was programed in MATLAB. At room temperature,the experimental forming limit data of AA7075-O aluminum alloy sheet were tested through the uniaxial tensile,wide plate bending and hydraulic bulging experiments. Meanwhile,the theoretical forming limit curves obtained by the modified M-K model and the traditional M-K model were computed respectively. By comparison,the modified M-K model is proved to be feasible and more accurate.