Effect of Composite Wrapping on the Stress Intensity Factors for Repaired Circumferentially Cracked Pipes

Pressure pipes may be damaged in different ways. These defects may initiate a fatigue crack, which will be first part-through, then through the thickness. There are several ways to repair the pipe. Gluing a composite sleeve seems to be the easiest and the cheapest. The hoop-wrapped cylinders with an internal circumferential semi-elliptical crack have bee modeled by the three-dimensional finite element method. The finite element model consisted of three subsections to model the cracked cylinder, the adhesive, and the composite wrap which are assembled to create the whole model. Crack front regions were modeled using singular elements, whereas the rest of the cylinder was modeled using isoparametri elements. The influence of the hoop-wrapped materials and the various crack parameters on the stress intensity factors is discussed. The study can be used as a design procedure for such repairing pipes.

Keywords:

Bonded composite wrap , Circumferential semi-elliptical crack , Finite element method , Pipe , Stress intensity factor