Strength of Graphite/Epoxy Bolted Wing-Skin Splice Specimens Subjected to Outdoor Exposure Under Constant Load and Yearly Fatigue Loading.
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER
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The results of an experimental study to provide long-term durability data on detailed full-scale graphiteepoxy wing-skin joint designs under environmental exposure and cyclic loading associated with commercial transport aircraft are reported. The specimens consisted of a single-row bolt configuration fabricated from T3005208 and a double-row bolt configuration fabricated from T3005209. The unpainted specimens were exposed to the outdoor environment under a sustained tensile load, and at yearly intervals, they were subjected to fatigue loading. Experimental results showed a slight reduction in residual tensile strength for both graphiteepoxy joints under the exposure times and fatigue loadings reported. A 7.5-percent decrease in residual strength was observed for the T3OO52O single-row joint after 5 years exposure and two lifetimes of fatigue loading. A 5.3-percent decrease in residual strength was observed for the T3005209 double-row joint after 7 years exposure and 2.8 lifetimes of fatigue loading. The 5208 epoxy material was more susceptible to degradation by ultraviolet radiation than the 5209 epoxy material
- Commercial and General Aviation
- Laminates and Composite Materials