Finite element modeling of superplastic forming of Weldalite™ (049) alloy

In this study, the finite element method was used to model the cone test made of a high strength superplastic aluminum alloy (Weldalite™ 049) that is used in aerospace applications. The cone test was modeled to study the effect of forming conditions such as temperature and strain rate on the deformation behavior during the process. In the model, the nonlinear finite element analysis package ABAQUS 5.8 was used. A creep material model expressing the strain rate in terms of the stress is used in the models and the material parameters were taken from the experimental testing results for the different temperatures and strain rates. Nonlinearity conditions considered were due to material and large deformation and due to contact and friction between the die and the sheet being formed. The temperatures and strain rates considered were 463 and 496°C and 1×10^-3, 5×10^-4, 1×10^-4 and 5×10^-5 s^-1 respectively. The results obtained included stress-strain relations for the biaxial deformation and strain and thickness distributions along the wall of the cone. Moreover, pressure-displacement curves for the mid-point of the sheet were predicted. Two cases were compared with the experimental results and showed very good correlation. The other cases were used to study the effect of changing the process parameters. Good correlation between the theory and the models was found.