A General Necking Criterion with Kinematic Strain Hardening
A general criterion for the prediction of necking in sheet metal forming is presented. We show that the onset of necking depends on the boundary conditions and that this phenomenon always occurs between two extreme modes: the diffuse mode and the localized mode. First, we use the necking criterion for orthotropic elastic-plastic materials with no induced anisotropy. Then, we apply the theory to materials with kinematic strain hardening. In order to validate the approach chosen, numerical results and experimental data are compared. Finally, the influence of the rheological parameters of strain hardening on the onset of necking is studied.
Jean-Pierre CORDEBOIS, Laurent MOURIC, Germaine NEFUSSI
forming limit curves, necking criterion, kinematic strain hardening.