Citation:
Xiang Zhang and Yazhi Li. Damage Tolerance and Fail Safety of Welded Aircraft
Wing Panels. AIAA Journal, Vol. 43, No. 7, July 2005, pp.1613-1623
Abstract:
An investigation is presented on fatigue crack growth behavior and fail safety
of integral stringer panels typified by welded aircraft fabrications. The
stringer panel is made of aluminum alloy 2024-T351 and fabricated by the
variable-polarity plasma-arc welding process. The sample simulates a part of the
lower-wing skin structures. Based on the linear elastic fracture mechanics,
numerical simulations are performed for two configurations, two-stringer and
nine-stringer panels, and three damage scenarios, in which welding-induced
longitudinal residual stresses are taken into account. A typical load spectrum
for large transport aircraft is employed for the analysis. For the two-stringer
panel life predictions have a reasonably good correlation with the test results.
Based on this validation, large-scale nine-stringer panels with three
manufacture options, that is, riveted, integrally machined, and welded integral,
are simulated for a skin crack under a broken central stringer propagating to
two-bay length. Useful comparisons are made among the three variants. Finally,
remedies to improve damage tolerance and fail safety of integral stringer panels
are explored. The incorporation of crack retarder straps bonded to the inner
surface of an integral panel has greatly improved the fail safety behavior of
the component with dramatically increased crack growth live.
