Investigation on the creep-age forming of an integrally-stiffened AA2219 alloy plate: experiment and modeling

Creep-age forming (CAF) is a relatively new sheet metal forming method for manufacturing large-scale components with accurate shape and desired performance. This paper fully investigates the strain distribution, springback characteristic, mechanical property, and shape quality of an integrally-stiffened AA2219 alloy plate during CAF process. A new set of unified creep-ageing constitutive equations incorporating the effect of pre-deformation is developed, and its effectiveness in FE solver MSC.Marc is validated by tension creep-ageing simulation. CAF simulation of the stiffened plate is conducted. The results indicate that the final shape of the plate is simultaneously determined by plastic and creep deformations, while the creep deformation plays a major role, with corresponding contribution percentage of 33 and 67%. Comparisons between experiment and modelling show that the deviations are approximately 11% for springback and 3.2% for yield strength, which confirms the validity of CAF modelling. Furthermore, yield strengths on the skin of the plate are more evenly distributed as compared with those on the stiffeners. In addition, the values of generatrix linearity of the formed plate are very small, which demonstrates that the CAF-formed integrally-stiffened plate has high-precision shape quality.