Effect of crack angle on the ultimate strength of cracked stiffened plates with CFRP

Abstract The steel structure of the ship hull often develops cracks due to fatigue, which damages the ship and may even lead to major accidents and economic losses. Therefore, it has become extremely urgent to find effective methods for repairing the cracks in the steel structure. This paper investigates the effect of Carbon Fiber Reinforced Polymer (CFRP) repair technology on the ultimate strength of cracked stiffened plates. The validity of numerical simulation is verified by comparing the results of finite element analysis (FEA) with experimental data. Based on this, the influence of crack angles on the repair effectiveness is analyzed. The results show that CFRP repair significantly enhances the ultimate strength, with repair efficiency increasing as the crack angle increases. The repair effect is optimal when the crack angle is 90°. This is because the ultimate strength of unrepaired specimens is inherently lower at a 90° crack angle, resulting in the highest percentage increase in strength after repair.