An enhanced method of evaluation for durability of marine structures

为了明确振动应力叠加对波动应力的影响，在撞击诱导的鞭笞应力下进行了疲劳试验和数值模拟。研究了残余应力对焊接残余应力下疲劳裂纹扩展的影响，特别是超载后的疲劳裂纹扩展。通过疲劳试验研究了强化的效果。针对腐蚀板，提出了一种生成随机腐蚀板表面的数值方法，并对腐蚀板的断裂进行了数值模拟，实验验证了该方法的正确性。最后，采用基于风险的方法对海洋结构的腐蚀强度进行了评估。

Fatigue tests and numerical simulation are carried out under slam-induced whipping stress, so as to clarify the effect of vibratory stress superimposed to wave-induced stress. The effect of residual stress is examined for the fatigue crack propagation under welding residual stress, especially after overloading. The effect of peening is also investigated by fatigue tests. Regarding corroded plates, a numerical method is proposed for the generation of a randomly corroded plate surfaces, and numerical simulation has been carried out for the fracture of corroded plates, which is verified by experiments. Finally, the strength of corroded marine structures is evaluated by a risk-based approach.