机翼用铝合金材料原始疲劳质量对比

当前航空工业的发展对于超高强铝合金材料的需求十分迫切，实现该材料的国产化并达到良好的质量效果至关重要。为了对中国航空工业中常用的7XXX新型铝合金材料的原始疲劳质量（IFQ）进行评估，选取裂纹萌生时间（TTCI）和当量初始缺陷尺寸（EIFS）作为对比参量，分别对中国飞机机翼用7XXX紧固孔试件和俄系BXXX紧固孔试件开展了低、中、高3种应力水平下的疲劳试验，通过对比分析得到了两种试件在不同应力水平下的TTCI趋于一致，最大仅相差3.71%；得到了每个试件的EIFS，应用疲劳统计学方法验证了两种试件材料各自的EIFS值无显著性差异；提出了一种不同超越概率下的结构细节当量初始缺陷模型，直接有效地对飞机结构细节的质量风险进行了评估；建立并对比分析了两种试件结构细节的通用EIFS分布，结果均小于中国军用手册规定的0.125 mm，且在超越概率为5%时，7XXX材料的通用EIFS值要小于BXXX材料的通用EIFS值。

Initial fatigue quality comparison of aluminum alloy materials for aircraft wings

The urgent demand for ultra-high strength aluminum alloy materials in the current aviation industry makes it extremely important to realize the localization of this material with desirable application effect. To evaluate the Initial Fatigue Quality (IFQ) of the new aluminum alloy material 7XXX commonly used in China's aviation industry, we select the Time To Crack Initiation (TTCI) and Equivalent Initial Flaw Size (EIFS) as the comparison parameters. Firstly, the fatigue tests of 7XXX fastening hole specimens for China's aircraft wings and BXXX fastening hole specimens of Russian series are conducted at three stress levels, i.e. low, medium and high, and the results show that the TTCI of the two specimens at different stress levels tend to be the same with the maximum difference being only 3.71%; the EIFS of each specimen is obtained, and the fatigue statistical method verifies no significant difference between these two values. A structural detail equivalent initial flaw model with different exceedance probabilities P is proposed to effectively evaluate the quality risk of the structural details of the aircraft. The general EIFS distribution of the structural details of the two specimens is established and compared. Both are smaller than 0.125 mm specified in China's military manual. In addition, when the exceedance probability is 5%, the general EIFS value of the 7XXX material is smaller than that of the BXXX material.