Prompt detection and management of imperfections, such as cracks or crack-like anomalies, in onshore and offshore oil and gas pipelines remain major challenges in pipeline maintenance. Accurate evaluation of failure pressure is therefore crucial to ensure safe and reliable operation. The failure pressures of pipelines containing surface cracks can be predicted using fracture mechanics–based analytical models, such as CorLAS and Ln-Sec, or through numerical tools. Among numerical approaches, the extended finite-element method (XFEM) enhances the traditional finite-element method (FEM) by enabling more effective modeling of crack growth through cohesive segment modeling, which employs a damage initiation criterion and a damage evolution law. Similarly, in fracture mechanics models, fracture toughness parameters are also either determined through standard fracture testing of the materials or derived from Charpy energy using empirical correlations. This study establishes an empirical correlation between Charpy-V-n (CVN) impact energy and XFEM damage properties, enabling high-fidelity failure pressure predictions in pipeline integrity assessments. Using full-scale burst test data and XFEM modeling in ABAQUS, the fracture energy (Gc) and maximum allowable principal strain (MAXPE) were calibrated. Results indicate that XFEM-predicted failure pressures align within ±8.8% of experimental values, outperforming traditional CorLAS and Ln-Sec models. The findings provide a computationally efficient alternative to full-scale fracture toughness testing, reducing dependency on J-integral and crack tip opening displacement (CTOD) experiments.
Zhang et al. (Tue,) studied this question.