Ballistic Impact Tolerance of Filament-Wound Composite Tubes with Rigid and Flexible Matrix Materials

摘要

The objective of this investigation is to evaluate the ballistic impact tolerance of filament wound composite tubes with rigid and flexible matrix materials. The flexible matrix composites (FMCs), consisting of carbon fibers embedded in an elastomeric polyurethane matrix, are under consideration for use in rotorcraft drivelines to fabricate a continuous, flexurally soft, torsionally stiff driveshaft. Rigid matrix composite (RMC) tubes were fabricated for the purpose of comparison at the coupon level. Filament wound angle-ply FMC and RMC tubes of [±45]_2 and [±60]_2 layups, 19.8-mm inside diameter, and 1.2-mm wall thickness were subjected to ballistic impact using a 4.76-mm-dia. steel ball launched at 306 m/s by a gas gun. Following impact, the extent of damage in the FMC tubes was evaluated using penetrant-enhanced x-ray radiography. Both types of tubes were subjected to tensile, compressive, and torsional tests to determine residual stiffness and strength characteristics. Energy absorption and the extent of damage as indicated by the full-field strain measurements (obtained during the axial tension and compression tests) were found to be greater in the FMC tubes than in the RMC tubes. Compressive and tensile strength reductions following impact were similar in both tube types. However, in torsion, the FMC tubes suffered a more severe loss of strength. For the two materials investigated, it appears that the more extensive fiber pull-out seen at the impact site in the FMC tubes leads to a greater loss in structural integrity when the fibers are most highly loaded, such as in torsion for the particular layups used in this investigation. In axial tension and compression, the fibers play a less important role in these layups. Therefore, little difference was seen in the axial strength reductions of FMC and RMC tubes due to impact damage.