Strength properties of aluminium/glass-fiber-reinforced laminate with additional epoxy adhesive film interlayer

This paper studies the strength analysis of two types of fibre-metal laminates (FMLs), with a different way of preparing the adhesive coupling between 2024-T3 aluminium alloy sheets and a polymer/fibre layer. In the first variant, the 3 M structural adhesive film AF 163-2 K is used as an intermediate layer between prepreg and adherends. The adhesive layer is co-cured with prepreg and adherends. In the second FML variant, coupling between adherends was produced using epoxy resin. Two types of strength test, - i.e., tensile/shear test and 90° peel test - were used to measure the adhesion between the layers of FML composite. To measure the joint strength the tensile test was used. The fracture mode and the fracture surfaces were examined and discussed using a scanning electron microscope. The application of the adhesive film as an additional binding agent caused an increase in laminate elasticity. In this way, the strength and fatigue life of the joint increased. The main advantage of adhesive film application was a significant increase in the peel strength of laminate, which reached 289.4%. As a result of this, bonded laminates are very susceptible to normal stresses. However, the application of the additional adhesive film in the analysed 2/1 laminate lay-up increased the mass of the laminate by about 10%. Furthermore, a significant increase in the FML peel strength was achieved, with the increased cost of the additional adhesive film at about 20%.