Fatigue properties of steel plates with single-edge-crack and reinforced by pre-CFRP

This study aims to investigate the fatigue properties of steel plates with single-edge cracks reinforced by carbon-fiber-reinforced polymers (CFRP) under different prestress levels. Theoretical analysis of the prestressed CFRP (Pre-CFRP) reinforcing steel plates and interface damage was conducted. Fatigue tests were conducted on five groups of specimens with varying prestressing levels and one unreinforced specimen to examine their failure modes and fatigue life. A combined component model of Pre-CFRP-reinforced steel plate, with a single crack, was established through ABAQUS and FRANC3D interaction analysis. The stress distribution of the steel plate after Pre-CFRP bonding was determined, and the adhesive layer damage variation with crack propagation was evaluated. The effects of CFRP reinforcement with different prestress levels on the stress intensity factor ( K ) and its amplitude ( ΔK ) were analyzed. In addition, the experimentally obtained a-N curves were compared with those derived using the finite element method (FEM). Finally, the inhibitory effects of CFRP reinforcement with different prestress levels on crack propagation were compared. The results demonstrated that in the tests conducted in the study, more severe interfacial debonding occurred in the prestressed specimens. The Pre-CFRP exhibits strong reinforcement effects, which can counteract some of the external loads, reduce the stress concentration at the crack tip, and reduce the K and ΔK , thereby extending fatigue life. A comparison between FEM and experimental results indicates a maximum crack propagation length error of 6.25%, validating the accuracy of the FEM.