Flight Simulation Fatigue Crack Propagation Evaluation of Candidate Lower Wing Skin Materials with Particular Consideration of Spectrum Truncation

摘要

Flight simulation fatigue crack propagation tests were carried out on 2024-T3, 7475-T761, and mill annealed Ti-6Al-4V sheet in thicknesses up to 3 mm. These materials are representative of transport aircraft lower wing skin stiffened panels of end load capacities 1.5 and 3 MN/m. Results show that the performance of 2024-T3 is much superior, owing mainly to greater retardation of crack growth after severe flights. The effect of load truncation is also greater for 2024-T3. The significance of the results in the choice of advanced structural concepts and materials as well as in the choice of truncation level is discussed. A recommendation for further investigation is given.