Experimental and numerical study of creep age forming of AA2050 plates with sparse multi-point flexible forming tool

Creep age forming of an Al-Cu-Li alloy (AA2050-T34) with an asymmetric tension/compression creep-ageing behaviour has been experimentally and numerically investigated in this study. Creep age forming experiments of plates with different thicknesses have been carried out to form doubly curved shapes using a recently developed sparse multi-point flexible forming tool. Corresponding FE model for creep age forming, incorporating the material model that describes the stress-strain relation and asymmetric creep-ageing behaviour of the alloy, has been developed through PAM-STAMP. The flexible forming tool can generate various tool shapes for creep age forming and is ideal for innovative trials. Stress concentration was found in some forming pin areas of the loaded plate. With larger initial loaded plastic strain and higher creep strain generated in these local areas, bumps may occur in formed shapes after creep age forming under certain circumstances. It is shown that the FE model is able to predict the formed shape accurately for thicker plates and can be used for tool set-up optimisation.