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腐蚀损伤会加速飞机结构的疲劳裂纹扩展,缩短飞机疲劳寿命。以LD2航空铝合金材料为研究对象,通过在实验室内模拟飞机服役环境进行加速腐蚀试验,得到不同腐蚀时间下的试验件,并在MTS-810疲劳机上对不同腐蚀时间下的试验件进行疲劳试验,得到不同腐蚀年限下的疲劳断口形貌。通过断口判读分析,得到不同腐蚀年限下的裂纹扩展数据(a,N)。从不同腐蚀时间下的裂纹扩展数据研究分析,得到裂纹长度与循环次数符合指数函数的形式,即裂纹扩展速率与裂纹长度成正比,其斜率依赖于腐蚀损伤与疲劳载荷两个因素,而且在同一应力水平下,其斜率与腐蚀时间呈线性关系,并且其截距与应力水平也呈线性关系。
Corrosion damage will accelerate the fatigue crack growth of the aircraft structure and shorten the aircraft fatigue life. Taking LD2 aviation aluminum alloy as the research object, the accelerated corrosion test was conducted in the laboratory by simulating the service environment of the aircraft to obtain the test pieces under different corrosion times, and the test pieces under different corrosion times were fatigue on the MTS-810 fatigue machine Test, fatigue fracture under different corrosion age. Through the fracture interpretation analysis, crack propagation data (a, N) under different corrosion ages were obtained. From the crack growth data under different corrosion time, the crack length and the number of cycles conform to the exponential function, that is, the crack growth rate is proportional to the crack length. The slope depends on two factors of corrosion damage and fatigue load, The stress level, the slope and the corrosion time was linear, and its intercept and stress levels also showed a linear relationship.