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在环境腐蚀损伤以及疲劳载荷的联合作用下,铝合金结构更容易萌生裂纹,威胁结构安全。腐蚀疲劳短裂纹扩展行为与长裂纹扩展行为差别很大,而且往往短裂纹阶段占据构件疲劳寿命的90%以上。通过对线弹性裂纹扩展模型进行修正,得到了预腐蚀弹塑性裂纹扩展表征模型,并对LD2铝合金进行预腐蚀疲劳验证性试验。结果表明,改进后的模型能够统一地表征预腐蚀弹塑性短裂纹和线弹性长裂纹的扩展行为,对于铝合金构件的腐蚀疲劳寿命预测和损伤容限评估具有重要的参考价值。
Under the joint action of environmental corrosion damage and fatigue load, the aluminum alloy structure is more likely to initiate a crack and threaten the structural safety. The corrosion fatigue short crack propagation behavior varies greatly with the long crack propagation behavior, and tends to account for more than 90% of the component fatigue life in the short crack phase. By modifying the linear elastic crack growth model, the model of pre-corrosion elastic-plastic crack propagation was obtained, and the pre-corrosion fatigue test of LD2 aluminum alloy was carried out. The results show that the improved model can uniformly characterize the expansion behavior of the pre-eroded elastoplastic short crack and the linear elastic crack, which is of important reference value for predicting the corrosion fatigue life and evaluating the damage tolerance of aluminum alloy components.