Specialty Materials, Inc.
BOEING Hy-BOR® HAT SECTION STUDY
A design and verification study was undertaken by the Boeing Phantom Works, St. Louis, MO to evaluate the potential structural benefits and cost impact of the selective use of Hy-Bor® hybrid boron fiber-carbon fiber prepreg tape in an advanced aircraft design.
Emerging composite hat stiffened skin designs for combat aircraft are using an approach where the inner moldline skin, web, and cap plies are continuous. This design approach has shown a performance benefit over discrete flange concepts, especially in high compression load applications. The objective of this study was to determine the structural efficiency benefits of Hy-Bor® in composite material design and to perform a manufacturing cost analysis. Using loads typical of a highly-loaded compression region of an advanced aircraft wing skin, this analysis task used Boeing software tools to optimize a composite baseline hat section design.
The design study revealed that, for the specific structure in the study, Hy-Bor® could be used in the cap portion of the integral hat stiffeners to reduce weight by 5%, at an additional cost of $851 per pound of weight saved. An additional benefit to the study design was a 28% reduction in hat height that might translate into a usable volume increase. The verification portion of the study confirmed the ability to meet and exceed the design ultimate load. Comparison to a baseline design with equal strength per unit volume capability reveals an 8% weight savings.
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Boeing Hy-Bor® Hat Section Study