Strength of aluminium resistance spot welded and weldbonded joints

The increasing restrictions in terms of safety and energy consumptions imposed in the transport vehicles construction promotes the use of new materials and new processes searching weight reduction. Lighter materials and better joining processes, like adhesive bonding can contribute to obtain some weight gain. Present work studies the shear strength obtained with weldbonding technique and compares it with the traditional resistance spot welding. The single lap joints were obtained with thin plates of 6082-T6 alloy and a high strength epoxy adhesive of two components (araldite 420 A/B). The strength of weldbonded joints was found to be significantly higher than equivalent spot welded joints. Numerical models were developed replicating experimental work. Nugget diameter was found to have a major influence in stiffness and stress level, while thickness reduction showed a much lower influence. The adhesive reduced significantly the stress level at the nugget root.