Fabrication Of Structural Components From Solution Coated Polyimide Prepreg

Recent advancements in high temperature materials at NASA Langley Research Center have led to the development of new polyimide resin systems with very attractive properties. The majority of the work done with these resin systems has concentrated on determining engineering mechanical properties from flat composite coupons. Since future advanced civilian aerospace components will require fabrication and testing of built-up structure from these high temperature composite materials, their processablity into structural components needed to be demonstrated.The NASA Langley-developed polyimide matrix resin, LaRC(TM)-PETI-5, was scaled to large quantities and solution prepregged onto Hercules IM7 carbon fiber by Fiberite Corporation. Using this prepreg which contained 20-22 percent N-methylpyrrolidinone solvent, techniques were developed to fabricated fully consolidated stiffener reinforced flat panels. The techniques included the use of movable metal tooling alone or in combination with trapped fluoroelastomer rubber. Methods were developed to remove all solvent prior to consolidation and to apply pressure uniformly to all sections of the part. Single stringer panels were made and machined into crippling and stiffener pull-off specimens. Panels with multiple stringers were also fabricated. Overall, the structural elements fabricated were of high quality and exhibited excellent mechanical properties.