Arresting Longitudinal Cracks in Steel Pipelines: Computational Analysis Technique

This research aims to study the arrest of crack propagation in oil or gas steel pipelines by using circumferential ribs as arresters. The use of ribs is much cheaper than high-grade steel with high fracture toughness. It has been shown that two ribs per pipe could prevent the most dangerous type of the pipeline fracture, which is a large length longitudinal crack. In this paper, two types of simplified estimations were used: the first is by calculations of stress intensity factors (K-I) and the second is by analysis of perfectly viscous (plastic) fracture. Both estimations were done on a pipe with plane wall and a pipe with ribs. The results showed that the sizes of ribs that can be technologically obtained increase the resistance of pipes to cracking by 30-50% and could be useful in preventing longitudinal crack propagation. Experimental verification of the results obtained on small-scale models has shown that there are some difficulties that can make direct transfer of results from small-scale model to full-scale structure impossible, and these difficulties are also discussed in this paper.