腐蚀条件下LD2航空铝合金裂纹扩展规律研究

doi:10.7527/S1000-6893.2013.0094

Abstract

Abstract:

Corrosion damage increases fatigue crack growth rates of aircraft structures, and shortens the fatigue life of an aircraft. Accelerated corrosion tests simulating the service environment of aircraft and then the fatigue tests on aerospace aluminum alloy LD2 test samples are executed under different corrosion times. The fatigue rupture morphologies of the test samples with different corrosion times are obtained. The crack growth data (a,N) under different corrosion times are measured by judgment of the rupture morphologies. By fitting the data (a,N), it is found that the relationship between crack length and cycle number is exponential, and the crack growth rate is directly proportional to the crack length, while the slope of the crack growth rate vs the crack length depends on the factors of corrosion damage and fatigue load level. Furthermore, by fatigue tests under different corrosion times and different stress levels, it is also found that the relationship between the slope and the corrosion time is linear under the same stress level and the slope values under different stress levels are nearly the same, while the intercept of the lines of crack growth rate also varies linearly with the stress level.

Key words: aluminum alloy, corrosion damage, fatigue rupture morphology, crack length, fatigue crack

CLC Number:

MU Zhitao, CHEN Dinghai, ZHU Zuotao, DING Wenyong, TIAN Shudong. Fatigue Crack Growth Behavior of Aerospace Aluminum Alloy LD2 Under Corrosion[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, doi: 10.7527/S1000-6893.2013.0094.

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Fatigue Crack Growth Behavior of Aerospace Aluminum Alloy LD2 Under Corrosion

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