Application of a Simplified Constant Crack Tip Opening Angle Model to Crack Propagation Analyses in Steel Pipelines

In this paper, a simplified constant crack tip opening angle (CTOA) model is presented and used to analyze two different pipeline steels. The steels examined in this work were an American Petroleum Institute (API) Standard X65 steel and a Japanese Industrial Standard (JIS) steel with the grade designation of STPG370. The commercial finite element (FE) code ABAQUS 2017x was used to generate the models and solve the analyses. The proposed propagation model was first verified through comparing the numerical results with published data. The steady-state fracture velocity data from the simplified model matched the data from literature within a maximum difference of 2% while drastically reducing the computational time required by an order of magnitude. Following the verification of the simplified model, it was then used to analyze recent experimental data. The model was able to match the experimental crack velocity data within a difference of 4%.