Structural Integrity Analysis and Verification for Aircraft Structures.
Final rept. 4 May-31 Sep 95,
ANALYTICAL SERVICES AND MATERIALS INC HAMPTON VA
Pagination or Media Count:
The object of this research was to characterize the effects of material age and environmental humidity on fatigue crack growth behavior of 2024-T3, 2024-T4, and 7075-T6 aluminum alloys. These alloys were taken from the fuselage and wing skin of USAF CKC-135 aircraft representative of the USAF Fleet of CKC-135 aircraft in age and mission use. The research was broken down into two activities Experimental testing and data reduction comparison. The test was designed to further the understanding of the effects of humidity on the aluminum alloys fatigue crack growth rate. The testing performed involved identical test specimen configurations of aged material subjected to loading while exposed to two different levels of wet and dry. These test results were compared to the results of similar test results involving relatively new materials to determine if there were any age effects. Of the three materials only A17075-T6 demonstrated humidity effects, and A12024-T3 demonstrated no age effects. The effect of age on fatigue crack growth rates of materials is minimal, while the effects attributed to corrosion appear much more severe.
- Transport Aircraft
- Structural Engineering and Building Technology