AERoBOND+ for Manufacturing Composite Structures

The AERoBOND and AERoBOND+ technologies are composite resin materials design innovations that enable new methods for composites joining and manufacturing. The resins are formulated with carefully selected off-set stoichiometries to delay/control the cure such that initial curing of individual components can be followed separately by joining/curing of components together. The ability to delay and control the co-cure joining step provides ease of manufacturing of multi-part composite structures, without compromising joint integrity. There are significant cost savings associated with eliminating fasteners and joint surface preparation steps. To date, the focus of the NASA development effort has been on novel epoxy-based prepreg formulations though other types of thermosets could be considered as well. The AERoBOND+ innovation provides an added adhesive layer to the AERoBOND joint design to improve the ability to join composite surfaces when these surfaces are less tightly matched. Conventional adhesives, e.g., film, paste, etc., are employed. By including an adhesive between the offset stoichiometric prepreg plies, the adhesive can fill the gaps between the bonding surfaces while maintaining reflowable AERoBOND layer interfaces. Since all interfaces are reflowable, they are much more tolerant of surface contamination, thereby mitigating a primary challenge for conventional adhesive bonding. The original AERoBOND technology was developed to enable co-cure joining and manufacturing of large composite structures without the use of fasteners. The AERoBOND technology provides novel prepreg and resin formulation designs to improve the joining and manufacturing of high-performance, large composite structures such as those used in aviation and aerospace applications. AERoBOND can also be used for many other prepreg-based composite structures, small and large, in many industrial applications. The joint quality can be exceptional, and the cost and efficiency of manufacturing is improved. The new AERoBOND+ innovation is a next-generation innovation that widens the scope of potential applications of AERoBOND to include those where the mating surfaces are less than ideally matched. This new innovation is accomplished with critically designed resin/adhesive/prepreg formulations and layer designs across the joint between each of the faying surfaces.