As part of the xLPR (Extremely Low Probability of Rupture) project, the stress intensity factor (SIF) solutions required for crack growth calculations were updated. This involved extension of existing solutions and development of new solutions as well. For surface cracks, the Universal Weight Function Method (UWFM) was implemented to handle complex stress distributions. In addition, a crack transition model was developed to more accurately capture the surface to through-wall crack transition. Finally, solutions for idealized through-wall cracks were extended to various pipe sizes and longer crack lengths.
In this paper, the SIF (K) solutions in xLPR Version 2.0 were validated against existing experimental data. The SIF modules in the xLPR code were used to simulate fatigue crack growth of circumferential cracks in pipes under bending up to wall penetration and to through-wall crack transition stage until idealized through-wall cracks were formed. The predicted fatigue crack growth results (mainly crack shape evolution) using the xLPR K-solutions provided good agreement with experimental data.