Two Prediction Methods For Ductile Sheet Metal Failure

Two analytical approaches are detailed for the determination of Forming Limit Diagrams (F.L.D.) and compared with experimental results. The first one is the 'Enhanced Modified Maximum Force Criterion EMMFC' and the second one is the 'Through-Thickness Shear Instability Criterion TTSIC'. The criteria are both written in an intrinsic analytical form and are applicable to linear and non-linear given strain paths as it occurs in any FEM codes for sheet-metal forming simulation. Finally, the two methods are complementary depending on the nature of failure and the predicted curves are in reasonable agreement with the trend of experimental results for a wide range of materials