Influence of carbon and glass fiber reinforced composite adhesive on the strength of adhesively bonded joints

Abstract Today, due to the frequent use of composite materials used in the aerospace and automotive industries, an intensive study is carried out on the joining methods of these materials. One method of joining composite or aluminum alloy materials is adhesive bonding. Studies on the development of the strengths of adhesively bonded joints focused on adhesive type, the bonding method, and hybrid joints. In the present study, a different method was used to increase joint strength. This study experimentally and numerically investigated the mechanical properties of single-lap joints bonded by a composite adhesive – obtained by adding fiber fabric to the adhesive. Adhesively bonded single-lap joints were produced using DP460 toughened adhesive type as the adhesives; AA2024-T3 aluminum alloy was used as the adherend, and carbon fiber and glass fiber fabric were used as the added fiber. In addition, for the numerical analysis of the presented study, the bulk properties of the composite adhesives were obtained. As a result, the use of fiber-reinforced adhesive in bonding joints significantly increases the failure load of the joint, as it prevents the progression of cracks formed in the joint. However, the increase rate in the failure load changes depending on the adhesive thickness and the type of fiber fabric. As follows, the failure loads of the fiber-reinforced joints increase between 5% and 41% compared to the non-fiber-reinforced joints. In addition, it was observed that the results obtained from the numerical analysis and the results obtained from the experiments were consistent with each other.