Aerostructural Trade-offs for Tow-steered Composite Wings
T. R. Brooks, J. R. R. A. Martins, and G. J. Kennedy
Journal of Aircraft, 57(5):787–799, 2020
The adoption of conventional “ black metal” composites in aircraft structures has lead to an improvement in performance over previous metallic designs. With the maturation of automated fiber placement, the design of unconventional composites featuring spatially varying tow orientations has become possible, but it is not yet clear how to utilize this new design freedom optimally. Wing design optimization studies are performed for three different material technologies: aluminum alloy, conventional carbon-fiber-reinforced composite, and tow-steered carbonfiber-reinforced composite. To explore the design trades of these materials, Pareto fronts for the competing objectives of fuel burn and structural weight are generated through gradient-based optimization. These two objectives serve as surrogates for the direct operating cost and acquisition cost of the aircraft, respectively. All optimized wings took advantage of some amount of passive load alleviation at the high-lift maneuver condition. Although the performance increase of tow-steered composite wings was not as dramatic as the performance increase of conventional composite relative to aluminum, the improvement was still significant. This work provides a methodology that can be used to explore tradeoffs in tow-steered wing designs and could be extended to other structural technologies.