Versatile Curatives for Room Temperature Honeycomb Repair

Composites are utilized extensively in modern aircraft, providing numerous benefits including extremely high stiffness-to-weight and bending strength-to-weight ratios.  The construction on aircraft flight control surfaces such as rudders, ailerons, spoilers, and flaps often consist of a core structure between two face sheets (skins).  While the face sheets are typically fabricated from thin composite laminates, the primary core materials utilized in aircraft components consist of honeycomb cell walls made of Nomex, fiberglass, or aluminum.  To repair these components, the damaged structure must be removed and replaced.  The materials used for these repairs require elevated cure temperatures, necessitating complex heating and monitoring equipment, or alternatively can take up to a week to cure at ambient conditions to achieve optimal properties.  There are many potential issues with honeycomb repair including increased localized weight, short working life, heat damage from exothermic reactions, and/or insufficient mechanical performance. To increase fleet readiness, reduce costs, and eliminate complex support equipment, the Navy requires a method to simplify and streamline honeycomb repairs.  To meet the Navy’s critical need, Luna Labs will combine extensive experience in streamlining current Navy composite repair processes with established rapid cure on demand resins, which our team developed for aerospace sealants, composite resins and epoxy concretes. Luna Labs will accomplish this by developing novel resin curatives for use with common, Navy-approved honeycomb repair materials.  These unique curatives will enable rapid room temperature cure with currently used resin systems, while maintaining a prolonged pot life, no significant exotherm, superior mechanical properties, and no need for specialized cure activation equipment.