Author(s)

R. Schiffmann, W. Bleck & W. Dahl

Abstract

By comparing the micromechanisms of ductile fracture of metallic materials (void nucleation, void growth and void coalescence) and the loading conditions in terms of local stresses and strains the fracture behaviour may be described in terms of local properties. Experiments on notched tensile specimens had been done to determine the plastic strain at crack initiation. FEM-calculations were used to calculate the parameters stress triaxiality and equivalent plastic strain during deformation at the point of void coalescence taking into regard the loading history. Strongly varying stress triaxiality during deformation was achieved by employing one- and two-step experiments with tensile bars of different notch radii. To find a criterion for void coalescence the following two models are ap

Keywords