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Damage Tolerance Methods for Airworthiness
This course is for the engineering professional currently working on aircraft structures damage tolerance evaluations for civil or military aircraft. The authors have 30+ years each in the aircraft industry. The course is broken up into two parts; 1.) Fatigue Loads and Spectra Development with discussions of FAA requirements and guidance, service versus design loads, service history, airframe fatigue load sources, mission profiles and usage, aircraft parameters, external loads, internal loads, load histories, dynamic effects, discrete events, spectrum development example, review of “single cycle” method, and special considerations. 2.) Damage Tolerance and Fatigue Evaluation of Structure with discussions of selecting details of interest - single load path, multiple load path, inspectable and non-inspectable; stress analysis - industry standard methods, finite element analysis; initial flaw sizes; stress intensity factors - corner cracks at a hole, corner cracks at a hole – flaw shape development, corner and through cracks at a hole, superposition and compounding, complex structure, bending restraint, bulging factor, R vs. Kmax and R vs. DK; materials - materials characterization; detectable crack lengths - probability of detection; fatigue crack growth models – Paris, Walker, Forman, Forman-Newman-de Koning; fatigue crack growth life - spectrum types, membrane, bending, bearing loading effects; residual strength; inspections - safeguard the airplane, how to develop an inspection program; DTA methods and examples - data required for approval, comparative analysis, small antenna installation, spot welded joints, MSD/MED.