Effect of using fibre reinforced epoxy adhesive on the strength of the adhesively bonded Single Lap Joints

In this paper, the static strength and elongation of the adhesively bonded Single Lap Joints (SLJs) at failure are enhanced by using glass fibres reinforced with epoxy adhesive. Commercially available Araldite, a standard epoxy adhesive, is utilised as the binding agent, while Aluminium plate and Glass Fibre Reinforced Plastic (GFRP) are used as metal and composite adherend materials, respectively, in the experiment. The performance of glass fibre reinforced epoxy adhesives in terms of strength improvement has been tested for two types of SLJs: MTM (Metal-to-Metal) and MTC (Metal-to-Composite). The strength controlling parameters considered during the experiment are certain variables such as the alignment of the bundle of long glass fibres along the loading direction, the size of glass fibres and the weight ratio of short glass fibres reinforced with epoxy adhesive in the overlap region of the SLJ. The effects of these controlling parameters on the strength and elongation have been discussed. In addition, the bundles of long glass fibres are overlaid at the fillet region along the loading axis, extending beyond the overlap ends to observe the effect of the peel stress at the overlap ends and examine its effect on the failure strength of the SLJ. The experimental results show that there is a substantial increase in failure load and elongation. Fractography analysis has also been carried out to analyse the fracture surfaces using a Scanning Electron Microscope (SEM).