Fracture Mechanics Analysis of Repairing a Cracked Pressure Pipe with a Composite Sleeve

Pressure pipes may be externally damaged in different ways: corrosion or notch due to diving machines. These defects may initiate a fatigue crack, which will be first part-through, then through the thickness. This results in a weakened region of the tube, then in leak of the pressure fluid contained in the pipe. There are several ways to repair the tube: changing the portion of tube, welding of extra metal in the defect, putting a welded metal sleeve, or gluing a composite sleeve. This last solution seems to be the easiest and the cheapest. The advantage is that the repairing sleeve is made on site and can be put with a given pre-tension. The work presented here is the numerical study of the fracture mechanics parameters of a part-through crack in a tube submitted to internal pressure and repaired with a composite sleeve. As there is a transfer of loading from the cracked tube to the repairing sleeve, the fracture mechanics parameters of the crack such as J-integral or opening of the crack lips will be modified. The study can be used as a design procedure for such repairing sleeves.