Identification of the interfacial fracture mechanism in the FRP laminated substrates using a modified single lap shear test set-up

• Interfacial fracture mechanism of laminated substrates is investigated in detail.
• A modified test set-up is developed to monitor the bond in laminated substrates.
• The significance of test set-up is noticeable under out of plane stresses.
• A new concept, optimum bondline thickness, is proposed based on experiments.
• A relationship is proposed for determination of the maximum load carrying capacity.

A modified single lap shear test set-up is implemented to monitor the fracture mechanism of the interface in fibre reinforced polymer laminated substrates. This set-up monitors the global slip of the laminate relative to the substrate and minimizes errors in order to provide more reliable results. By changing the adhesive thickness and laminate width, the effect of these two parameters is studied during the tests. A new concept, optimum bondline thickness, is proposed and formulated based on post processing of the experimental outcomes which is explained in detail by micro- and macro-cracking mechanism in the interface.