Ductile fracture of high strength steels with morphological anisotropy, Part I: Characterization, testing, and void nucleation law

Abstract The ductile fracture behavior of a high strength steel is investigated using micromechanics-based approach with the objective to build predictive framework for strain and crack propagation under different loading conditions. Part I this study describes experimental results determination elastoplastic damage nucleation stress triaxiality Lode parameter values. mechanism starts early void from elongated inclusions, either by particle cracking oriented along major axis, or matrix decohesion when main transverse. Void followed plastic growth coalescence. long inclusion axis preferentially aligned in one direction leading significant failure anisotropy transverse being almost 50% lower compared longitudinal one, even though isotropic. data are first used calibrate model. An enhanced anisotropic model then developed integrated into Gurson–Tvergaard–Needleman scheme. parameters identification finally performed validated towards results. All these elements subsequently II simulate full all testing specimens entire spectrum states, final failure.