Steel rings are frequently used as crack arrestor devices in steel gas tran
smission pipelines to prevent the possibility of long running axial cracks.
These arrestors have the effect of reducing the pipe opening as the crack
propagates. This decreases the available crack driving force and, as a resu
lt, crack arrest can take place. This essentially is a second line of defen
ce against catastrophic failure in the event that crack initiation cannot a
lways be prevented. This paper describes a novel analysis methodology that
has been developed to investigate the suitability of these crack arrestors.
This is based on a fluid/structure/fracture interaction package, PFRAC. He
re, a curved beam element has been implemented into PFR;IC to simulate the
behaviour of the arrestor. The contact conditions between the pipe wall and
the arrestor, along with the various computational procedures, are describ
ed here. Several numerical results for a cracked pipe with arrestors are pr
esented along with comparisons with pipes that do not have arrestors.