The application of some criteria for ductile fracture to the prediction ofthe forming limit of sheet metals

The possibility of the application of ductile fracture criteria to the form ability prediction of sheet metals is examined. Some criteria in simple for ms are employed and combined with the finite element simulation of sheet me tal forming. From the calculated histories of stress and strain in each ele ment, the fracture initiation site and the forming limit are predicted by m eans of the criteria for ductile fracture. The material constants in the cr iteria are determined from uniaxial and plane-strain tension tests. The cal culations are carried out for the axisymmetric deep drawing of various alum inium alloy and steel sheets. A comparison between the calculated and exper imental results shows that the present approach using the ductile fracture criteria gives fairly good predictions. (C) 1999 Elsevier Science S.A. All rights reserved.