Effect of reinforcement phases and post-cure temperature on adhesively bonded hybrid patch repair in indented glass/epoxy composite laminates

ABSTRACT This paper focuses on the experimental investigation on the effect of different fiber reinforcement phases and post-cure temperature to improve the strength recovery of adhesively bonded patch repair in glass/epoxy composite laminates. The repair was performed on the site of damaged region in the laminates by using various configurations of patches such as chopped glass (CG), chopped glass/carbon (CGC), chopped glass/kevlar (CGK), ply-by-ply glass (PG), ply-by-ply glass/carbon (PGC), ply-by-ply glass/kevlar (PGK), stitched glass (SG), stitched glass/carbon (SGC), and stitched glass/kevlar (SGK). The result reveals that the SGK hybrid patch repaired laminates offered a strength recovery by 101.5% as compared with damaged laminates. Further, the SGK hybrid patch was subjected to post-cure temperatures of 50°C, 70°C, 90°C, and 110°C which were considered based on the glass transition temperature (Tg) of glass/epoxy laminates. The result shows that the SGK hybrid patch with a post-cured temperature of 50°C has equal strength with virgin laminates and the strength recovery was improved by 112.9% as compared with damaged laminates. This study concluded that the adhesively bonded hybrid patch repair with a post-cure temperature of 50°C can be used for various fiber-reinforced polymer (FRP) industries to repair laminated composites.