A springback prediction method for a cylindrical workpiece bent with the multi-point forming method

An analytical method is proposed to predict springback and residual stress distribution of the multi-point formed cylindrical workpiece. Considering the loading model of the multi-point forming process, the bending moment can be obtained by superimposing the bending moment generated by each punch, which is calculated through the stress in the thickness direction. The springback value and the residual stress in the tangential direction are obtained theoretically. The strain and stress variation in the thickness direction during the loading and unloading process are also analyzed. The finite element (FE) simulation and the bending experiment (EXP) are conducted to make a comparison with the analytical (ANA) results. The results show that the proposed method can effectively predict the springback value and the residual stress distribution in multi-point forming of a cylindrical workpiece.