English abstract
Using Fiber reinforced polymer composite laminate to strengthen or repair damaged
pipelines has been widely adopted in Oil and gas industry. They have been proven to
be able to increase the operating pressure and the lifetime of the repaired pipe. Hence
it is very important to properly evaluate the performance of the composite laminate
repair. In this study, pressurized blister test was used to evaluate the effect of different
repair geometries on the Failure Pressure. First, a flat plate test specimen with a
circular through wall defect and GFRP composite laminate repair was prepared. Then
a blister test was conducted to study the interfacial debonding between the repair
laminate and steel surface. The different geometries experimentally studied are pipe
defect size, FRP repair thickness, fiber orientation, repair size and surface roughness.
Experimental results reveal that a larger defect size leads to a smaller failure pressure
whereas a larger repair thickness increases the failure pressure. Test results show that
defect size and the repair thickness greatly affect the repair performance. Whereas the
fiber orientation, repair size and surface roughness have minor effect on the failure
pressure. Furthermore the blister test represents a good and reliable alternative to
hydrostatic test in evaluating repair performance.
