Accession Number : ADA302075

Title :   Development of Graphite/Polymide Honeycomb Core Materials.

Descriptive Note : Contract rept.,

Corporate Author : LOCKHEED-CALIFORNIA CO BURBANK

Personal Author(s) : Stone, R. H.

PDF Url : ADA302075

Report Date : SEP 1978

Pagination or Media Count : 71

Abstract : Honeycomb panel constructions consisting entirely of graphite/polyimide composites were developed and evaluated. Graphite/polyimide composites, were used in the honeycomb core webs and in pre-cured sandwich skins. Polyimide adhesives were also developed and evaluated for use in skin-core bonding. The purpose of this program was to develop light weight sandwich constructions for high temperature applications which could provide comparable shear strength and stiffness to metallic honeycomb constructions. In the initial program phase, honeycomb core was developed by Hexcel Corp. using NR-150A2:B2 resin with 1000 tow Thornel 300 fabric reinforcement. Sandwich panels were fabricated using NR-150A2:B2 as a cell edge adhesive, and tested at 550 deg F before and after 500 hours aging. In the second program phase, honeycomb cores were fabricated and tested with NR-150B2 and FMR-15 resins with HM-S fabric reinforcement. A new polyimide adhesive, LARC-13, was evaluated as a skin-core adhesive. Panels were fabricated and tested at 550 deg F before and after 500 hours aging. The test results confirmed that graphite honeycomb construction provides comparable mechanical properties at lighter weights than metallic honeycomb panels. The NR-150B2 system was satisfactory for 550 deg F service, but 550 deg F appears to be a marginal use temperature for the other systems. The LARC-13 appears to be an excellent skin-core adhesive, and the NR-150 was also satisfactory applied as a cell edge coating. The HM-S fabric proved less satisfactory as a reinforcement than Thornel 300, both from processability and resin-fiber compatibility considerations.

Descriptors :   *COMPOSITE MATERIALS, *GRAPHITED MATERIALS, *HONEYCOMB CORES, *HONEYCOMB STRUCTURES, *POLYIMIDE RESINS, TEST AND EVALUATION, METALS, MECHANICAL PROPERTIES, CELLS, EDGES, HIGH TEMPERATURE, PANELS, STIFFNESS, GRAPHITE, COATINGS, CONSTRUCTION, LIGHTWEIGHT, ADHESIVES, SANDWICH CONSTRUCTION, SANDWICH PANELS, SHEAR STRENGTH.

Subject Categories : Laminates and Composite Materials
      Structural Engineering and Building Technology

Distribution Statement : APPROVED FOR PUBLIC RELEASE