Application of Enhanced Gurson-Like Ductile Damage Models to Simulate Crack Growth in Pipeline Steels Under Wide Range of Constraint Conditions

Abstract For the safe design and operation of high-performance pipelines, it is important to characterize the crack growth behaviors (using J-R curves) for pipeline steels under a variety of constraint conditions, so that reliable pipeline integrity assessments can be performed. The finite element method (FEM) based on an enhanced Gurson-like ductile damage model was used to investigate the ductile crack growth behaviors on pipeline steels. The standard Gurson-Tvergaard-Needleman (GTN) model cannot account for several ductile damage anisotropies. This limitation narrows the applicability of the GTN model to constraint conditions similar to the data used to calibrate the model. It is demonstrated in the present study that the implemented enhanced model significantly improves upon the GTN model and can accurately predict the ductile fracture behavior over a wide range of constraint conditions based on limited calibration data. The ductile damage model was used to analyze ductile crack growth behaviors in single-edge notched bending (SENB) and single-edge notched tension (SENT) specimens. Several SENT crack geometries were analyzed, representing a wide range of constraint conditions. The numerically calculated crack growth resistance curves were compared to the experimental J-R curves and curves developed using the original GTN model.