A comparative study on adhesive properties of nanoparticle reinforced epoxy bonded single-strap repaired composites

Abstract This study aimed to evaluate the impact of nanoparticle inclusion and patch size on the bonding performance of single-strap repaired glass-reinforced composite plates through experimental investigations. Epoxy adhesive was modified with three different nanoparticles: nano-silica (NS), nano-graphene (NG), and nano-clay (NC) at varying weight contents. The patch repair performance of the test samples was evaluated using two patch ratios (Patch diameter ( D )/Hole diameter ( d ) = 2 and 3) to explore the influence of patch size on repair effectiveness. GFRP composite base plates having a 10 mm diameter hole in the middle were patch repaired by using patches with the same material. Tensile tests were conducted to compare the tensile performance of the repaired composite samples, and the results were compared with the samples with and without holes. Based on the findings, it was noted that samples with a larger patch ratio ( D / d = 3) can withstand higher tensile loads compared to those with a patch ratio of 2. Moreover, it was found that the specimen repaired with 3 % by weight NC-filled epoxy adhesive showed the greatest increase in tensile load value. This increase was recorded at both patch rates, with a percentage improvement of 2.8 and 19.54 % compared to pure epoxy adhesive. Also, it was observed that when the patch ratio was 3, the 3 % NS-filled adhesive showed an increase of 3.3 %. On the other hand, all combinations of NG-filled adhesive showed a decrease in maximum tensile load values.