Experimental and Numerical Studies to Strengthen the Adhesive Bonded Single Lap Joint

Abstract

In this work, an attempt has been made to strengthen the adhesive bonding using various concepts like hybrid joints, dual and mixed adhesive bonded joints. One of the most commonly occurrence of defect in adhesive bonded joints are the weak bonds. Hence, weak bond effects in single and dual adhesive bonded joints also have been investigated. Initially, numerical studies have been carried out on adhesive bonded joints and hybrid joint between carbon fibre reinforced plastic (CFRP) and aluminium adherends. From this study it is found that the hybrid joints increases the interface strength there by reducing the peel and shear stress at the ends of the bonded joint. But still, the hybrid joints are not recommended for all applications because riveting requires initial drilling of the adherends that introduces localized damage and the damage area is strongly concentrated around the rivet. Additionally, drilling of CFRP laminate is not recommended because of delamination and fiber damage near the hole. Hence, in the following studies, dual adhesive concept has been considered to strengthen the adhesive bond between different similar and dissimilar adherends. Then, experimental and numerical studies have been carried-out on single and dual adhesive bonded lap joints between different adherends. AV138 brittle and Araldite-2015 ductile adhesives are used alone in the bonded region as single adhesive bonded joints. In dual adhesive bonded joints, AV138 brittle adhesive is used in the middle of the bonded region at different dimensions and Araldite-2015 ductile adhesive is used at the ends of the overlap because of high shear and peel strength. The numerical results are closely matching with the experimental results. From this studies it is found that, the use of dual adhesives helps in increasing the bond strength between CFRP and aluminium adherends. Further in this direction, experimental and numerical studies of single and dual adhesive bonded joint concept have been continued using different adhesives between simila...