Study on the stress intensity factor of FRP-repaired cracked steel plates

The externally-bonded fiber reinforced polymer (FRP) technique has been used to repair steel structures in recent years. As an essential parameter to analyze the crack propagation and fatigue life of cracked steel elements, the stress intensity factor (SIF) can be utilized to assess the repair effectiveness of FRP laminates. In this paper, a finite element (FE) analysis was conducted to evaluate the SIF of cracked steel plates repaired with FRP laminates using ANSYS software. Effect of three FRP configurations on the SIF at the crack tip was investigated under the condition of the same amount of FRP laminates. Parameters influencing the SIF were also discussed, including the crack length, the thickness of FRP, the elastic modulus of FRP, the shear modulus of the adhesive, and the thickness of the adhesive. FE results showed that the SIF of FRP-repaired specimens can be significantly reduced compared to the un-repaired specimens. FRP configurations had an obvious effect on the SIF at the crack tip. The increase of the FRP thickness, the elastic modulus of FRP, and the shear modulus of the adhesive can decrease the SIF, and the thicker adhesive resulted in a higher value of SIF.