Ductile Fracture of TRIP780 Sheets under Multi-axial Loading

Abstract

The loading path to fracture in multi‐axial experiments is determined through hybrid experimental‐numerical analysis. A series of multi‐axial fracture experiments are carried out on specimens extracted from TRIP780 steel sheets. It involves three different types of full‐thickness specimens: notched tensile specimens, tensile specimens with central hole and disc specimens for punch testing. The experimental program characterizes the onset of fracture over a wide range of stress states between uniaxial tension and equi‐biaxial tension. Using an anisotropic Hill’48 plasticity model, the evolution of local stress and strain fields is evaluated through detailed finite element analysis of each experiment. The accuracy of this hybrid experimental‐numerical loading history identification is evaluated by comparing the local digital image correlation measurements with the FE predictions. In particular, uncertainties affecting the identification of the state of loading at the onset of fracture are quantified.