Akpinar, Salih; Ozel, Adnan

Particularly findings from nanoscience influence materials and mechanical sciences deeply as well as other disciplines. Polymers containing nanostructures attracted attention as nanocomposite materials. This study involves the production of a new nano adhesive utilizing the advantageous parameters of carbon-nano-reinforced polymers used for adhesively bonded, particularly in aerospace applications, and the mechanical and thermal cycle performance of this new product. In this study, the tensile mechanical properties of single-lap joints (SLJs), which are the most widely used type of adhesive joint geometry, obtained by adding nano-particle to adhesive was investigated experimentally and numerically under ambient temperature and thermal cycle conditions. The experimental results of reinforced adhesive under ambient temperature conditions were taken from open literature. Adhesively bonded SLJs were produced using DP460 tough and DP125 flexible adhesive types as the adhesives; AA2024-T3 aluminum alloy was used as the adherend and 1 wt% Graphene-COOH, Carbon Nanotube-COOH and Fullerene C60 were used as the added nano-particles. The experimental results were compared with the results of numerical calculations that employ Cohesive Zone Model (CZM). Also six different thermal cycle loadings were applied on the SLJs. As a result, when the experimental failure loads were examined, the nanocomposite adhesives obtained by adding nano-particle were found to have increased the thermal cycle resistance of the joints. However, increase rate in the thermal cycle resistance changes depending on the structural features of the adhesive, the type of nano-particle and thermal cycle condition. It was also concluded that the results of numerical calculations matches the experimental results quite satisfactorily.

Akpinar, Iclal Avinc; Gültekin, Kürşat; Akpinar, Salih; Akbulut, Hamit; Ozel, Adnan

Especially findings from nanoscience and nanotechnology, which have progressed significantly in recent years, influence materials and mechanical sciences deeply as well as other disciplines. In this study, the failure loads of single-lap joints (bonding joints used in space, automotive and aerospace applications)bonded by a nanocomposite adhesive – obtained by adding nanostructure to the adhesive – were experimentally examined to increase the failure load of adhesively bonded joints. Adhesively bonded single-lap joints were produced using DP460 toughened adhesive type, DP270 rigid adhesive type and DP125 flexible adhesive type as the adhesives; AA2024-T3 aluminum alloy was used as the adherend, and Graphene-COOH, Carbon Nanotube-COOH and Fullerene C60 were used as the added nanostructures. Furthermore, to examine the effects of nanostructure reinforcement ratios in the adhesive at joint-failure load, three nanostructures with different ratios of 0.25%, 0.5%, 1%, 2% and 3% were added. As a result, when the experimental failure loads were examined, the nanocomposite adhesives obtained by adding nanostructure were found to have increased the load failure of the joint. However, increase rate in the failure load changes depending on the structural features of the adhesive and the type of nanostructure. Moreover, in the geometries of single-lap joints produced in this study, the best nanostructure reinforcement ratio, in terms of the failure load of the joint, was 1% percent by weight.

Akpinar, Iclal Avinc; Gültekin, Kürşat; Akpinar, Salih; Akbulut, Hamit; Ozel, Adnan

Due to their great advantages, adhesively bonded joints are frequently used in many areas like automotive, marine, space and aerospace industries. Especially findings from nanoscience and nanotechnology, which have progressed significantly in recent years, influence adhesives sciences significantly as well as other disciplines. In the present study, nanoparticles were added to the adhesive to increase the damage load of adhesively bonded single lap composite joints and tensile and bending moment damage loads of these joints were experimentally investigated. In the study, carbon fiber fabric reinforced composites (0/90°) with Plain Weave were used as the adherend; rigid, tough and flexible adhesive types were used as the adhesive and 1 wt% Graphene-COOH, Carbon Nanotube-COOH and Fullerene C60 were used as the nanoparticles. As a result, based on the AA2024-T3 aluminum alloy used in a study conducted by Akpinar et al. [1], the use of carbon fiber fabric reinforced composites as the adherend considerably increases the damage load of the joint, depending on the adhesive type. Moreover, when failure loads obtained from experiments were examined, the addition of nanoparticles to the adhesive was shown to increase the tensile and four-point bending damage load of joint, depending on the adhesive and nanoparticle type.

Gültekin, Kürşat; Akpinar, Salih; Gürses, Ahmet; Eroglu, Zafer; Cam, Salim; Akbulut, Hamit; Keskin, Zeki; Ozel, Adnan

This study experimentally determines the tensile failure load of the nanocomposite adhesive - obtained by adding nanostructures to the adhesive - using four different methods in single-lap joints. For the study, adhesively bonded single-lap joints were produced by using DP460 liquid structural epoxy as the adhesive, AA2024-T3 aluminum alloy as the adherend and graphene as the nanostructure. When the failure load obtained from the experiments was examined, it was seen that, while the nanostructure-reinforced methods indicated in the literature have a great effect on the failure load of the joint and the standard deviation, a new method developed in this study increased the failure load of the joint and minimized the standard deviation. These improvements increased the reliability and reproducibility of the joint.