Fatigue and quasi-static analysis of a new type of surface preparation used for the CFRP repair of steel offshore structures

Abstract

ABSTRACTIn recent years, there has been an increasing interest in repairing offshore steel structures by using adhesively joined carbon fiber reinforced polymers (CFRP). For such procedure, surface preparation plays a vital role to maintain the integrity of the joint and to ensure proper load transfer. The primary surface preparation used by the oil and gas industry is the grit blasting due to its known quality. However, the logistic required is a major drawback limiting the use of adhesively joined repairs. Other surface preparation procedures available are unable to promote proper treatment. In this paper, an alternative surface preparation methodology employing a portable machine that uses rotation and impact to treat the steel surface was evaluated by quasi-static and fatigue tests of CFRP/steel adhesively bonded using the double-lap joints. The joints were prepared using non-corroded and severely corroded steel surfaces treated by grit blasting or rotating impact machine. The corroded plate was used to evaluate the efficiency of the rotating impact machine in removing deeply penetrating oxides. Test results showed that the performance of the machine was comparable to grit blasting even for the severely corroded surface with deep pitting. Corrosion in the metallic substrate impaired the quasi-static and fatigue properties.