Mechanical performance and bond-slip constitutive model of CFRP-steel interface

This article examines the interface performance and bond-slip constitutive model of carbon fiber-reinforced polymer (CFRP) reinforced steel structures using both experimental analysis and theoretical evaluation. The aim is to explore how various design parameters influence these interfacial properties. Using the bond–slip relationship model, we derive an analytical solution for the distribution of interfacial stress for the bonded CFRP-steel lap joint. Subsequently, the theoretically calculated interfacial shear stresses at different loads are meticulously compared with the experimental values. Remarkably, the stress transfer region and trends in the calculated curves show excellent agreement with the experimental data. Moreover, this study investigates how various material parameters, such as the bonding length, elastic modulus, and thickness of CFRP and steel plate, influence the interfacial stress. When the bonding length of CFRP exceeds the effective bonding length, the increase in length has a negligible impact on interfacial stress. Using CFRP with a higher elastic modulus and greater thickness effectively reduces stress concentration at the bonding ends. Changing the elastic modulus and thickness of the CFRP has a more pronounced effect on the interfacial shear stress near the free end of the steel plate and the tensile stress of the CFRP laminate, while exerting a smaller influence near the free end of the CFRP laminate. Conversely, the elastic modulus and thickness of the steel plate have a greater impact on the interfacial shear stress and tensile stress near the free end of the CFRP laminate, while having a lesser effect near the free end of the steel plate.