Trends to determine fracture intiation and propagation of a pipe under service pressure

A fracture toughness transferability curve has been established for the X52 pipe steels described by a linear relationship between the notch critical stress intensity factor and the average value of T stress over the opening stress distribution. This curve is used to determine the fracture toughness associated with the structure. the characteristic length of the fracture process. Crack extension modelled by Finite Element method using CTOA criterion coupled with the the node release technique is used to predict the crack velocity, the arrest pressure and crack length. This method is compared with the different Two Curves Methods Batelle, HLP and HLP-Sumitom