Investigation of Rousselier model and Gurson-Tvergaard-Needleman model in ductile fracture of ...

In this research, the micromechanical Rousselier damage model, which is not available in commercial software was accomplished with a subroutine in Abaqus finite element analysis software. Ductile fracture behavior of API X65 steel was evaluated by simulation of tensile test of smooth and round notch bar specimens of base metal in hoop direction and weld metal. The Rousselier model and its parameters of this model were determined for API X65 steel based on experimental data. In this work the Rousselier and Gurson damage model was compared for API X65 steel. Results of tensile test and simulation for Gurson model show inaccuracy in final stage of load-displacement plot. This is because the Gurson model assumes that the fracture surface is flat and shear fracture does not occur in specimens, but in Rousselier model consider the shear fracture. The Rousselier model shows more accurate results compared with experimental data in final stage of loading. Furthermore the Rousselier model shows little error comparing with experiment around maximum load since the void growth due to nucleation is ignored in this model. Also, the Rousselier model shows better convergence when the grooving radius of tensile test specimen increasing but the Gurson model behaves differently.