Abstract:
Composite materials have been used to structurally repair piping and other facilities for many years.
However, the original use of composite materials was for repairing corroded pipelines where the
intent was to restore strength to the damaged section of the pipeline. In addition to repairing
corrosion, composite materials have successfully been used to repair dents, wrinkle bends, induction
bends, and pipe fittings including elbows and tees as well as repair of offshore risers. In this study,
the behaviour of both circumferential and longitudinal through cracks in repaired pipe with bonded
composite wrap, subjected to bending moment, internal pressure and tension is investigated using
three dimensional finite element analyses using Abaqus as a code compute. In the first part of elastic
domain, stress intensity factor is utilized as a fracture criterion, then in the second part of the elastic
plastic domain Rice integral is utilized as a fracture criterion. The effects of the mechanical and
geometrical properties of the adhesive on the variation of the stress intensity factor and J integral, at
the crack front were also analyzed. The obtained results show that the presence of the bonded
composite repair reduces significantly SIF and J, which can improve the residual lifespan of the
pipe. Meanwhile, SIF and J are also reduced as the elastic and the geometrical wrap properties are
improved, particularly when the Young Modulus of the adhesive and the wrap thickness are
increased.
