文档介绍：47th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Confere AIAA 2006-2059
1 - 4 May 2006, Newport, Rhode Island
Reliability Based Aircraft Structural Design Pays Even with
Limited Statistical Data
Erdem Acar1 and Raphael T. Haftka2
University of Florida, Gainesville, FL, 32611-6250
Probabilistic structural design tends to apply higher safety factors to inexpensive or
light-ponents, because it is a more efficient way to achieve a desired level of
safety. We show that even with limited knowledge about stress probability distributions we
can increase the safety of an airplane by following this paradigm. This is plished by a
small perturbation of the deterministic design that maximizes safety for the same weight.
The structural optimization for safety of a representative posed of a wing, a
horizontal tail and a vertical tail is used to demonstrate the paradigm. We find that moving
small amount of material from the wing to the tails leads to substantially increased
structural safety. Since panies often apply additional safety factors beyond those
mandated by the Federal Aviation Administration (FAA), this opens the door to obtaining
probabilistic design that satisfies also the FAA code based rules for deterministic design. We
also find that probabilistic design is insensitive to mitted while assessing the stress
probability distribution of the deterministic design, which is the starting point of the
probabilistic design. This suggests that using the deterministic design as the basis for the
probabilistic design insulates the latter from the extreme sensitivity to statistical data that
have been observed in the past. Finally, we find that for ponents subject to
the same failure mode, the probabilities of failure at the probabilistic optimum are
approximately proportional to the weight. So ponent which is ten times lighter than
another should be designed to be about 10 times safer.