Mechanics of aircraft lap joints
Accurate prediction of aircraft joint fatigue is complex, as multiple factors can influence fatigue crack development.
These factors include: the fastener interference fit, clamping force, fretting damage, applied load, load distribution and corrosion damage. Corrosion treatments applied during maintenance have been shown to act as a lubricant, redistributing stress. Fatigue crack development can be affected by this redistribution, causing variation in the fatigue life. In order to explore this phenomenon, a representative aircraft joint test coupon has been designed and manufactured.
Accompanying detailed analytical and finite element models - and future testing of the joint structure - will advance understanding of aircraft joint mechanics, including the effects of corrosion treatments. This will provide benefits to aircraft structural integrity programs through informing maintenance scheduling and corrosion management and, thus, improving the operational availability and safety of aircraft platforms.
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