Theoretical prediction of the springback of metal sheets after a double-curvature forming operation

By establishing a mechanics model and corresponding analytical procedure based on the membrane theory of shells of revolution and an energy method, a theoretical prediction of springback is formulated for thin metal sheets after they have undergone a double-curvature forming operation, e.g. stamping and stretching-bending. The strain-hardening of the material is incorporated into the mechanics model. The effect of stretching force applied at the edge of the plates on springback is also considered. Excellent agreement is found between the theoretical prediction of springback and experiment results. It is shown that the procedure developed is capable of quantitatively predicting the springback of circular and square plates after axisymmetric stamping with a relatively minor effort of calculation and a good accuracy. (C) 1999 Elsevier Science S.A. All rights reserved.