Determination of fracture toughness of an adhesive in civil engineering and interfacial damage analysis of carbon fiber reinforced polymer–steel structure bonded joints

Carbon fiber reinforced polymer–steel structural bonded joints are often subject to mixed-mode loading i.e. coupling action of normal and shear stress occurs in the joints. In this paper, an experimental approach based on fracture mechanics was adopted to obtain the fracture toughness (G ΙC and G ΙΙC ) of an adhesive currently employed in civil engineering applications, with the corresponding pure cohesive models verified by numerical results. Furthermore, feasibility of the mixed-mode cohesive model for the current adhesive was validated through comparison of numerical and experimental results of carbon fiber reinforced polymer–steel single-lap joints. Finally, based on the validated mixed-mode cohesive model, the interfacial damage of carbon fiber reinforced polymer–steel beam joints was analyzed using the finite element method, accounting for the long-term degradation that can occur in the joint materials i.e. carbon fiber reinforced polymer and adhesive. The work in this paper can provide some useful data such as the fracture properties of the adhesive and shed some light on the design optimization of carbon fiber reinforced polymer–steel structure joints as well as the estimation of its long-term interfacial behavior when in service in civil engineering applications.