Room Temperature Shelf-Life Pre-Impregnated Carbon Fiber Fabric for use in Out of-Autoclave Aircraft Repair

During the Phase II effort, TRI/Austin will continue development work on a new composite pre-preg technology that will provide extended room-temperature shelf-stability with single vacuum bag processability. Based on accelerated aging tests of pre-preg samples, the predicted shelf stability is up to two years in an ambient temperature environment. Under anaerobic vacuum bagging conditions, the cure speed of the pre-preg is rapid, being less than two hours at 200 oF. The Phase II Base period will be used to further verify the ability of the developed pre-preg resin materials to provide extended shelf-life, mechanical and thermal properties, and aircraft fluid resistance. The candidate pre-preg material will also be used fabricate a demonstrator repair patch bonded to a pre-cured laminate. Modifications to the pre-preg matrix resin will be made to adjust shelf stability and cure rate. Candidate pre-preg will be prepared to perform additional accelerated life testing for determination of shelf-life. Aged pre-preg will also be used to fabricate composite test panels to measure the effect of pre-preg age on composite mechanical and thermal properties. The reinforcement to be used for production of the pre-preg will be a plain weave carbon fiber fabric. The laminate panels prepared will be used to perform elevated temperature/humidity conditioning exposures to determine retention of mechanical and thermal properties. Additional composite panels will be exposed to two aircraft fluids for the same purpose. After environmental and fluid exposure conditioning, the composite panels will be screened for the ability to meet a sub-set of mechanical and thermal property requirements. Tasks will also be performed to transition the pre-preg technology to a production environment. A series of prototype production runs will be performed iteratively to optimize the resin for processability. Pre-preg from these runs will be used to validate the thermal and mechanical properties of composite laminates. Product specifications will be developed, and the downselected pre-preg materials will be produced to perform interlaboratory validation testing to qualify for use within Intermediate Maintenance Activities (IMA’s) or Depot Maintenance Facilities. A comprehensive transition plan will be developed with accompanying documentation of the final product specifications.