Connections have always been one of the fundamental challenges for engineers across various industries. From ancient times to the present, a range of connection methods-such as bolts, rivets, welding, adhesives, and more have been employed. Each method comes with its own strengths and weaknesses; for instance, bolted connections are robust and easily disassembled but can lead to stress concentrations around holes and add weight to the structure; riveting offers a permanent, lightweight bond but requires access from both sides and is hard to undo; welding provides high-strength joints with efficiency up to ۱۰۰% of the base material's strength, though it may alter thermal properties and cause distortion; and adhesive bonds deliver uniform stress distribution and reduced weight, yet they are sensitive to temperature and humidity and demand precise surface preparation. Adhesive connections have recently attracted greater interest in industries thanks to their many benefits, including enhanced fatigue resistance, even stress distribution, electrical insulation, lighter overall structures, a cleaner appearance without visible holes or fasteners, reduced corrosion, the ability to join dissimilar materials (e.g., metal to plastic), and dual roles as both a connector and sealant. Nevertheless, uncertainties often arise when comparing adhesive connections to spot welding in terms of performance. Clearly, the strength of spot welds depends on various welding parameters (like electrical current, welding time, and electrode force), nugget diameter, sheet thickness, material properties (such as thermal and electrical conductivity, carbon and silicon content), and surface coatings. Likewise, adhesive strength is influenced by the adhesive type, loading conditions (e.g., tensile or shear), and the overlap area. This article aims to create single lap joint connections using both spot welding and adhesives, then test them under tensile loading to determine which demonstrates superior strength.
