Accelerated Adhesive Cure for Nutplate Repair

ABSTRACT: The F-35 Joint Strike Fighter uses metal nutplates to secure fasteners in areas that have no backside access at the time of installation.These nutplates are attached with a two-part adhesive which currently requires a 24 hour cure at room temperature.This long cure time negatively impacts the aircrafts availability if an aircraft comes back to the depot and they have a disbond of a nutplate that requires repairs.The Air Force desires quick repairs to get the aircraft back in the air and in missions within 5 hours.To achieve this goal new methods are needed for an accelerated adhesive cure for nutplate repairs.Texas Research Institute Austin, Inc (TRI/Austin) will establish technical feasibility by demonstrating the accelerated adhesive cure system for nutplates on the F-35 will meet the operational and environmental requirements.The technical hurdles will be addressed with laboratory environment testing and performance characterization through experimentation.The accelerated cured nutplates will be tested to critical shear strength, peel strength and impact strength and compared to the 24 hour cured adhesive.The accelerated curing system will also be required to meet explosion proof criteria as jet fuel vapors may be present during the repair.; BENEFIT: The team will develop a business case analysis and transition plan to ensure that this new accelerated curing system will be available to the military as well as the commercial market.The immediate benefit is increasing the F-35 availability by reducing nutplate repair time.Production and repair of military aircraft as well as future military air vehicles will benefit from this technology. The commercial aircraft industry will also find this technology useful in the joining of composites.