Fatigue performance test on inclined central cracked steel plates repaired with CFRP strand sheets

An experimental study was conducted on central-cracked steel plates with different crack inclination angles that had been repaired with carbon fiber reinforced polymer (CFRP) strand sheets. Initial cracks with five different inclined angles (0–60°) were artificially induced from a central hole of steel plates. All the cracks had the same projection length, running perpendicular to the loading axis. Crack lengths, crack trajectories, failure modes and the effects of different repair configurations were investigated, and fatigue crack propagation lives were compared. A typical adhesive failure mode, oblique compression failure in the adhesive layer, was observed. A conclusion was drawn that fatigue life was directly determined by the projection length, while the projection length was calculated from the initial crack length and inclination angle. The average fatigue life extension ratio of specimens with single-sided repairs was 1.44; that of specimens with double-sided repairs was 3.03.