进行2024-T3铝合金标准中心裂纹拉伸试件4种典型环境下的裂纹扩展试验,以试验数据为基础,通过对一般环境下的裂纹扩展模型进行修正,建立腐蚀环境下的裂纹扩展模型。对试验结果的分析处理表明,该模型能够很好描述各种典型腐蚀环境下裂纹稳定扩展阶段的裂纹扩展速率,能够较准确估算裂纹扩展寿命,腐蚀修正系数清楚地反映腐蚀影响的程度。通过对单一介质环境腐蚀修正系数的加权组合,模型可以推广应用于复杂环境下裂纹扩展分析。该模型便于充分利用现有材料裂纹扩展性能的数据。

The influence of environmental corrosion on fatigue life of 2024-T3 aluminum alloy is investigated in this paper. Experiments with center-hole specimens and CC (T) specimens are conducted and reported. The test result shows that the corrosion influence is becoming serious while the environmental causticity is increasing, and the influence on crack initiation life is greater than that on crack propagation life. Analysis of the test data also indicates that the environmental causticity enlarges the dispersivity of fatigue life. Using the corrosion-modification-factor obtained by eigenvalue or mean value to prediction the fatigue life with high reliability will cause an unconservative conclusion.

采用腐蚀条件下的细节疲劳额定值(DFR)方法对民机机身典型长桁机加接头结构进行了综合环境下的疲劳分析。结合分析过程，给出了由细节模拟试件试验得到的DFR腐蚀影响系数确定结构综合环境的DFR腐蚀影响系数的方法，并采用民机机身长桁机加接头部位模拟试件，完成指定使用情况所对应的预腐蚀-腐蚀疲劳交替验证试验。 试验结果与分析结果的对比表明，结果基本一致，综合环境下疲劳分析方法可行。

采用2024-T3铝合金含中心孔试件进行了实验室空气环境和潮湿空气环境下的疲劳寿命实验及升降法实验，研究了潮湿空气环境对2024-T3铝合金疲劳性能的影响．结果表明，潮湿空气环境显著降低了2024-T3铝合金的疲劳性能，潮湿空气环境对其疲劳寿命特征值和疲劳强度均值的影响系数分别为O.6059和0.8722；在潮湿空气环境中疲劳寿命的分散性变大，用疲劳寿命的中值或特征值得到的腐蚀影响系数进行可靠度95％的腐蚀环境下的寿命修正，将得到偏危险的结果．用潮湿空气环境对基本可靠性寿命的影响系数由标准g-Ⅳ曲线折算得到的对疲劳强度的影响系数与升降法测得的对疲劳强度的影响系数基本一致，在潮湿空气环境下标准g-Ⅳ曲线参数仍然适用．

Crack propagation tests were conducted with CCT specimens made by 2024-T3 Aluminum alloy in benign and corrosive environments to investigate the stochastic characteristics of crack growth. A random variable probability crack growth model, base on the modified form of Paris law, was used to characterize the stochastic performance. Distribution significance test has been done, which shows that the random variable X can be considered reasonably to follow log-normal distribution in all the 4 kind of environments. Variance analysis indicates that the scatter in wet air is greater than that in laboratory air significantly. Expressions for the probability distribution of crack size at any given loading cycle and the probability distribution of the random fatigue life at which a given crack size is reached were discussed. The corresponding calculations for the crack length distribution and P-a-N curves with certain reliability were carried out. The comparisons with experimental data indicate the validity of the proposed method.