Synergetic effect of adhesive bonding and welding on fracture load in hybrid joints

Abstract

Joining of components with adhesive bonding (AB) is a wide-spread technique that distributes the load over a greater area than mechanical joints. However, peak stresses at the overlap edges can lead to premature failure. In the current study a novel procedure was used to solve this problem by using a hybrid weld joint to decrease the stress concentration at the edges. Due to the different mechanisms of joining, AB and welding cannot be combined in one place since interactions degrade the mechanical performance of both joints. Therefore, in this study, the focus was to manufacture a hybrid joint where additional sheets were manually welded at the overlap edges of the adhesively bonded lap joint. By doing so, bilateral effects such as burning of the adhesive by welding and weld defect formation due to presence of adhesive layer were eliminated. Tensile shear tests were carried out to determine the fracture load of the adhesive, welded and hybrid joint. The fracture surfaces were examined to determine the fracture mechanism. Numerical simulations were performed with stress analysis and fracture prediction to observe the stress distribution. The hybrid joint showed superior mechanical tensile strength and deformation, when compared against the AB and welded joint. The simulation results showed that the location of the maximum stress in the hybrid joint is in the middle of the span which is in contrary to AB joints wherein the maximum stress occurs at the edge. This caused a synergetic effect of both AB and welding leading to superior mechanical properties. The resulting findings potentially provide insights for the development of new hybrid joining configurations delivering improved performance.

Keywords

• Hybrid joint
• Adhesive bonding
• Fracture load
• Peeling effect
• Synergetic effect