AERoBOND: Large-scale Composite Manufacturing

This technology (AERoBOND) enables the assembly of large-scale, complex composite structures while maintaining predictable mechanical and material properties. It does so by using a novel barrier-ply technology consisting of an epoxy resin/prepreg material with optimal efficiency, reliability, and performance. The barrier-ply materials prevent excessive mixing between conventional composite precursors and stoichiometrically-offset epoxy precursors during the cure process by forming a gel early in the cure cycle before extensive mixing can occur. The barrier ply is placed between the conventional laminate preform and the stoichiometrically-offset ply or plies placed on the preform surface, thus preventing excessive mass transfer between the three layers during the cure process. In practice, the barrier ply could be combined with the offset ply to be applied as a single, multifunctional surfacing layer enabling unitized assembly of large and complex structures. The AERoBOND method is up to 40% faster than state-of-the-art composite manufacturing methods, allows for large-scale processing of complex structures, eliminates the potential for weak bond failure modes, and produces composites with comparable mechanical properties as compared with those prepared by co-cure. NASA Langley Research Center has an improved method for making composite structures. Industrial composite manufacturing is primarily accomplished through three methods: co-cure, co-bond, and secondary bond processes. Co-cure produces predictable structures and joint properties but is costly and challenging to implement on large, complex structures. Co-bond and secondary bond processes have greater applicability to complex structures but produce unpredictable material interfaces and properties. NASAs AERoBOND technology presents a method for manufacturing composites at scale with the reliability of co-cure in a bonded assembly process. AERoBOND utilizes novel epoxy and barrier ply layers with optimized chemical and physical properties to enable the bonding of large, complex composites with the advantages of co-cure assembly but without the need for redundant fasteners, thus reducing assembly time and cost.