Surface to Through-Wall Crack Transition Model for Circumferential Cracks in Pipes

In the present paper, finite element analyses were performed to update and also extend the applicable ranges of the existing KI and COD solutions for non-idealized through-wall cracks. Then, a surface to through-wall crack transition model was proposed based on these solutions. The proposed model provides a criterion which determines when the final surface crack should transition to a through-wall crack. It also provides a criterion to determine the two crack lengths (at the inner and outer diameter surfaces) of the initial non-idealized through-wall crack. Furthermore, crack growth of non-idealized through-wall cracks can be simulated by using the proposed method. Finally, the proposed model was verified by demonstrating that it can well predict the surface to through-wall transition behavior when compared to the natural crack growth simulations.