Manufacturing of Aircraft Structures Using Composite Tailoring Techniques

Aircraft structures have unique design requirements for lightweight materials that maintain integrity under a full envelope of loading conditions. Carbon-epoxy structures have been used to replace heavier traditional metallic structures, particularly as composite materials can be fabricated with advanced tailoring techniques to further improve weight and stiffness characteristics. These advanced tailoring techniques have been researched at NASA Langley Research Center at the Integrated Structural Assembly of Advanced Composites (ISAAC) facility as part of the Advanced Air Transport Technology (AATT) project. This paper contains a discussion of the manufacturing of four wing cover panels that were fabricated as part of a 15-foot structural test article that contained tailored geometry and laminate styles. Two of the cover panels contained integral stiffeners, which are stiffening elements interleaved between skin plies, while the other two panels contained tow steering, which uses curvilinear paths to steer fibers during placement. Discussion topics include topology optimization, automated fiber placement (AFP) programming, manufacturing best practices and challenges encountered, and key findings on considerations required for successful cure and part integration.