Effect of graphene nano-particle reinforcement on the fatigue behavior of adhesively bonded single lap joints

In this study, the effect of GNP reinforcement ratio on the tensile, fatigue and post-fatigue tensile behavior of single-lap adhesive joints was experimentally investigated. In the study carried out, 3M DP460 was used as adhesive material and carbon fiber reinforced composite material was used as the adherend material. Graphene nanoparticles were used to reinforce the adhesive material used in the study. 0.25%, 0.5% and 1% GNP by weight were added to the adhesive material. Single lap joints were created using reinforced and non-reinforced adhesives. The tensile strengths of the obtained single overlap specimens were determined by subjecting them to the tensile test. After determining the tensile strengths, fatigue behaviors were determined by performing fatigue tests at 60%, 50%, 40%, 30% and 20% of tensile strength. In order to determine the change in tensile behavior after fatigue loading, fatigue loads at 30% of the tensile damage load were performed and fatigue tests were stopped at 50,000, 100,000 and 200,000 cycles. The effects of GNP ratio and fatigue loading on the tensile behavior were investigated by subjecting the specimens subjected to fatigue preload to the tensile test. The study results showed that GNP reinforcement increased the bond strength. However, the highest bond strength was observed in samples containing 1% by weight GNP. The highest fatigue strength was observed in the samples containing 0.50 wt% GNP. While the fatigue strength of the samples containing 1% GNP was higher than the unreinforced samples, it was lower than the samples containing 0.50% GNP. When the tensile behavior after fatigue loading was examined, the joint strength decreased as the number of fatigue cycles increased in all of the unreinforced and reinforced samples.