The paper describes the design, analysis, and testing of a full-scale section of an F-111 aft fuselage center body made from advanced composite materials. A 160-in.-long test component was fabricated and tested to destruction. The composite material systems were graphite/epoxy, boron/ epoxy, boron/aluminum, and glass/epoxy. Maximum use of composites was maintained throughout the structure, with both skins and substructures being treated. Design concepts for the various structural elements were developed through a program of testing of subelement specimens. Test results were obtained on the strength of boron and graphite composites applied to sandwich panels, stiffened sheet panels, frames, bulkheads, and fittings.
A static test component was detail designed and fabricated. Fourteen subassemblies of frames and panels were fabricated and assembled into a 920-lb component using 460 lb of composite material. A weight saving of 18 percent of the counterpart aluminum and steel structure was obtained. Static testing of the part included loading in bending with simultaneous application of internal pressure. The component sustained 130 percent of the design ultimate load. Deflection gage and strain gage data showed excellent agreement with analytical results.