A coupled microvoid elongation and dilation based ductile fracture model for structural steels

• Microvoid elongation evolution relationships are derived for ASTM A992 steels.
• New coupled damage model is proposed for ductile fracture in ASTM A992 steels.
• Model is implemented in Abaqus® as a user defined material (UMAT).
• Calibration and validation of the model is conducted using axisymmetric specimens.
• The model accurately predicted damage modes and ductile fracture strains.

This paper presents the formulation, implementation, calibration and validation of microvoid elongation and dilation based continuum damage model (MED-CDM) for ductile fracture simulation. The damage evolution in this model is derived from micromechanical analyses that accounts for the microscopic damage due to microvoid elongation and dilation. The proposed model is implemented in Abaqus® finite element program, and is calibrated and validated using existing experimental data for a range of stress triaxialities. The proposed model is shown to accurately predict the load displacement behavior, fracture strains, fracture initiation locations and the underlying microscopic damage mechanisms that are responsible for the fracture initiation in ASTM A992 structural steels.