MT-1620 al.2002 Fatigue (cyclic loading Effect on material properties Damage growth EXample A fighter aircraft has a gross take-off weight of 30,000 lbs. In a test of one wing, the wing fails at a total loading of 243,000 lbs. What is the margin of safety? Definition of m.o.s. Tested Ultimate-Ultimate Ultimate We know Tested Ultimate 243.000 lbs (for one wing) How do we get the Design Ultimate? Design Ultimate Design Limit x Factor of Safety For aircraft FOS=1.5 Paul A Lagace @2001 Unit 2 -p. 7MIT - 16.20 Fall, 2002 • Fatigue (cyclic loading) - Effect on material properties - Damage growth Example A fighter aircraft has a gross take-off weight of 30,000 lbs. In a test of one wing, the wing fails at a total loading of 243,000 lbs. What is the margin of safety? Definition of M.O.S. = Tested Ultimate - Ultimate Ultimate We know: Tested Ultimate = 243,000 lbs. (for one wing) How do we get the Design Ultimate? Design Ultimate = Design Limit x Factor of Safety For aircraft, F.O.S. = 1.5 Paul A. Lagace © 2001 Unit 2 - p. 7