Evaluation Of Kevlar 29 For Filament-Mound Structural Applications In Helicopters

Because of its reputed high tensile strength and intermediate tensile modulus, Kevlar 29 is a prime candidate for use in a proprietary program at Hughes Helicopters, Inc. The proposed components will be fabricated using wet-filament winding and an epoxy resin. Since K-29 is not widely used as an epoxy-impregnated structural material, detailed data on its mechanical properties is not available. In a test program conducted to obtain such data, the following tests were performed: - Impregnated strand. -Short beam shear and bending (unidirectional specimens), -In-plane shear (45 degree specimens), -Fatigue testing (performed on bending specimens). To complement the data obtained above, unidirectional tubular specimens were tested statically and in fatigue to generate specific design allowable data. As a result of this program, the importance of a compatible finish on K-29 for epoxy-resin filament winding became apparent. The commonly used oil finish, which is used in the textile and rope industries, is not suitable for use in a structural composite; therefore, other finishes were evaluated, including "unfinished" and a filament winding finish.