不同损伤尺寸铝合金结构疲劳寿命分散性研究

飞机损伤结构疲劳寿命分散系数是分析损伤结构疲劳寿命分散程度的重要参数。针对飞机常用铝合金材料，开展预置损伤试验件疲劳测试。采用相关系数比较法，判断损伤结构剩余疲劳寿命分布类型；通过断口观察和数据统计处理，分析损伤与疲劳寿命关系及含损伤结构剩余疲劳寿命分散性规律。结果表明：含损伤结构剩余疲劳寿命更加符合威布尔分布；含预置损伤结构较未预置损伤结构疲劳寿命下降明显，随预置损伤尺寸增加，结构剩余疲劳寿命逐步降低，剩余疲劳寿命分散性增大，不同初始损伤结构疲劳寿命分散性差异较大。本文研究为建立飞机不同损伤尺寸铝合金结构疲劳寿命分散系数模型提供参考依据。

Study on fatigue life dispersion of aluminum alloy structures with different damage sizes

Fatigue life scatter factor of aircraft damaged structures is an important parameter to analyze the fatigue life dispersion degree of damaged structures. In this paper, the fatigue test of prefabricated damage test pieces is carried out for aluminum alloy materials commonly used in aircraft. The distribution type of residual fatigue life of damaged structures is determined by correlation coefficient comparison method. The relationship between damage and fatigue life and the dispersion of residual fatigue life of damaged structures were analyzed through fracture observation and statistical data processing. The results show that the residual fatigue life of damaged structures is consistent with Weibull distribution. The fatigue life of the structure with preset damage decreases obviously compared with that without preset damage, and the residual fatigue life of the structure decreases gradually with the increase of preset damage size. With the increase of the preset damage size, the residual fatigue life dispersion increases, and the fatigue life dispersion of different structures with initial crack damage is different. The work in this paper provides a reference for establishing fatigue life scatter factor models of aluminum alloy structures with different damage sizes.