Organic-matrix composites are increasingly replacing traditional metallic materials in aerospace platforms due to their high strength to weight ratios, manipulative properties, and corrosion resistance. However, repair methods for these materials are considerably more complicated. Typically, a composite laminate repair patch must be manually fabricated on-site from dry fabric and resin and then bonded to the damaged structure. Prior to the bonding or co-curing, a Double Vacuum Debulk (DVD) process is performed on the lay-up, requiring a separate piece of support equipment. The procedure requires dedicated equipment and is time consuming, costly, and size limited. In addition, the repaired structure is not brought back to full strength. A more efficient and effective on-aircraft process is required. To meet the Navys needs, Luna will develop a single vacuum bag process utilizing advanced bagging materials which will achieve high quality aerospace laminates while eliminating the DVD process tooling and size restrictions. Furthermore, Luna will offer enhanced versions of the standard resins and adhesives to enable cure on-demand systems for quick repairs that can be readily accomplished on-site. Luna will consult with Bell Helicopter to ensure that the technology is relevant to aerospace systems.
Benefit: The initial focus of this program will be on development of an efficient and effective method for rapid, on-site repair of composite aerospace structures for the Navy. The technology will be directly implementable to Navy and other Department of Defense platforms which utilize composite materials. However, the impact on the broad composite commercial market could be enormous. The technology is applicable to virtually every industry where composites are utilized as it covers a wide range of composite material systems, fabrication processes, and applications. It is anticipated that an advanced breathable compaction material, impenetrable to resin, will be developed to produce high-quality composite materials from simple vacuum bag fabrication processes. This will enable escape of air and reaction gasses while maintaining uniform compaction force to eliminate voids and processing imperfections. The technology will have extreme impact for out of autoclave fabrication methods, although it will be of benefit to autoclave processing as well. Cure on-demand resin and adhesives will also be developed, providing materials with prolonged pot life that can be quickly cured with a short duration of elevated temperature. Use of these systems will provide economical composite manufacturing options by reducing fabrication costs and increasing production capabilities.
Keywords: VARTM, VARTM, Aircraft Repair, Composite Fabrication, composite repair
