Springback prediction method for double-curved workpiece considering plate anisotropy in multi-point forming

Springback is adversely affected by mechanical anisotropy in the process of sheet metal forming. In this work, an analytical method was proposed to predict the springback of the double-curved workpiece in multi-point forming process. To characterize the anisotropy of the AA7B04 aluminum plate, the plate was divided into several layers along thickness direction. And in each layer, the calculation of bending moment was done respectively based on von Mises, Hill's 48 and Yld2004-18p yield criterion. After springback, the neutral surface curvature was calculated and the profile of the neutral surface was constructed by the Bezier surface blending method. To verify the prediction method, finite element simulation and bending experiment were performed. The results show that the predictive accuracy of the method was more accurate than that with the isotropy model. Additionally, the most accurate constitutive model to describe the in-plane anisotropy of AA7B04 aluminum was the Yld2004-18p yield criterion.

Automated summary

In this study, an analytical method was proposed to predict springback of double-curved workpiece in multi-point forming process. The anisotropy of the aluminum plate was characterized by dividing it into layers and calculating bending moment based on different yield criteria. The method was found to be more accurate than isotropy model, with Yld2004-18p yield criterion being the most suitable for describing the in-plane anisotropy of AA7B04 aluminum.