New numerical tools to calibrate the Two Curves Method using the CTOA criterion

Abstract Based on the Crack-Tip Opening Angle (CTOA) fracture criterion and the finite element method coupled with the node release technique, a New Two-Curve method (TCM) was proposed for the prediction of gas pipelines' crack arrestability. Arrest pressure, crack propagation velocity and length were predicted successfully. A modern high-toughness pipeline made in API 5L X65 pipeline steel with 19 mm wall thickness and a 355 mm external diameter was investigated. The critical CTOA ( CTOA C ) property was measured with a Modified Compact Tension (MCT) specimen at room temperature. A new method for evaluating the CTOA C by combining experimental load–deflection data and finite element analysis was implemented. The results of the CTOA C were compared with the available CTOA C data. The results for the New Two-Curve method were discussed and compared with those obtained by well-established methods such as Battelle-TCM, HLP and HLP-Sumitomo.