Fatigue and Fracture of Thin Metallic Foils with Aerospace Applications

Metallic honeycomb structures are being studied for use as thermal protection systems for hypersonic vehicles and as structural panels in other aerospace applications. One potential concern is the growth of fatigue cracks in the thin face-sheets used for these structures. To address this concern, the fatigue behavior of thin aluminum base alloy sheets ranging from 30 m to 250 m in thickness was investigated. The effect of material roll direction was also considered at 30 m. In all cases, the fatigue crack growth rates were found to be one to two orders of magnitude higher than that of the same material of greater thickness. In addition to data for fatigue crack growth rate, data are also presented for the effect of thickness on the fracture toughness of these materials.M.S.Committee Chair: Dr. Erian A. Armanios; Committee Member: Dr. David L. McDowell; Committee Member: Dr. Massimo Ruzzen