Cohesive failure assessment in CFRP-repaired perforated steel tubular members under bending moment

The use of composite materials to repair corroded structures in the offshore industry is an evolving practice. Thus, to ensure the effectiveness of the repair, it is necessary to understand the structure's responses under the different kinds of loads that involve its use. The repair's success does not rely just on the laminate's components but also on its proper adhesion to the substrate. This study examines carbon fiber laminate-repaired steel tubes that had concentrated corrosion-caused perforation damage and assesses their performance using numerical models and experiments with 1:3.5 scale samples under a pure bending moment load-scenario. To minimize stress concentration and mitigate the debonding risk, bevels were placed at the repair ends. The adhesive cohesive failure at the steel-composite interface and particularly at the ends of the repair are studied, as is the influence of the bevel geometry. Overall, the numerical model predictions lie close to the experimental result, suggesting that bevels can significantly reduce damage at the interface between steel and composites, and they can even prevent cohesive damage.