Fatigue life prediction of aviation aluminium alloy based on quantitative pre-corrosion damage analysis

基于量化预腐蚀损伤分析的航空铝合金疲劳寿命预测（英文）

A new method of quantitative pre-corrosion damage of aviation aluminium(Al-Cu-Mg)alloy was proposed,whichregarded corrosion pits as equivalent semi-elliptical surface cracks.An analytical model was formulated to describe the entire regionof fatigue crack propagation(FCP).The relationship between the model parameters and the fatigue testing data obtained in thepre-corroded experiments,crack propagation experiments and S-N fatigue experiments was discussed.The equivalent crack sizesand the FCP equation were used to calculate the fatigue life through numerical integration based on MATLAB/GUI.The resultsconfirm that the sigmoidal curve fitted by the FCP model expresses the whole change from Region I to Region III.In addition,thepredicted curves indicate the actual trend of fatigue life and the conservative result of fatigue limit.Thus,the new analytical methodcan estimate the residual life of pre-corroded Al-Cu-Mg alloy,especially smooth specimens.

针对航空铝合金(Al-Cu-Mg),提出了一种量化预腐蚀损伤的新方法,该方法将腐蚀坑当量成半椭圆表面裂纹。通过预腐蚀试验、裂纹扩展试验和S-N疲劳试验构建了用于描述疲劳裂纹扩展(FCP)完整阶段的分析模型,并讨论了模型参数与这些疲劳试验数据的关系。基于MATLAB/GUI软件,采用数值积分方法,将当量裂纹尺寸和FCP模型用于计算疲劳寿命。结果表明:FCP模型拟合的S形曲线可以表示裂纹扩展第一阶段至第三阶段的整体变化。此外,预测曲线显示出疲劳寿命的实际变化趋势,并从中获得了疲劳极限的保守结果。因此,对于预腐蚀Al-Cu-Mg合金,尤其是光滑试样,这种新的分析方法可以估算材料的剩余寿命。