Rigorous SIF-based prediction of fatigue life improvement for prestressed-CFRP-repaired cracked steel plates.

Carbon fiber reinforced polymer (CFRP) can be widely used to repair damaged plates in marine engineering equipment. To predict the fatigue life improvement by this repair, the stress intensity factor (SIF) of the cracked plate without/with repair is analyzed rigorously. Specifically, the SIF of a cracked plate without repair is analyzed and the error due to the finite element model (FEM) mesh is evaluated by comparing with the exact solution. By applying the same mesh having the same error, the exact SIF of the repaired plate is obtained in a convenient form. Fatigue experiments reveal that the same crack propagation parameters (C and m) can be applied for the unrepaired/repaired plates. Based on those, the prediction equation of fatigue life is obtained for cracked steel plates repaired with prestressed CFRP. The results show that this prediction method has the advantages of simplicity and efficiency. • The stress intensity factor (SIF) of an unrepaired/repaired cracked plate is investigated, and the convenient form of the exact SIF of the repaired plate is obtained by using the "proportional method". • It is found that crack expansion rates of unrepaired/repaired plates can be expressed by almost the same equations. • The correctness of prediction equation for prestressed-CFRP-repaired cracked steel plates is verified by fatigue test. • The enhancement effect of prestress on the fatigue life of cracked steel plate is quantitatively investigated. [ABSTRACT FROM AUTHOR]