Applications of Hybrid Composites to Hydrofoil Structures

Studies are presented on application of advanced composites to hydrofoil structural components such as struts and foils. It is shown that to satisfy the strut/foil structural requirements and constraints, the most cost-effective and structurally efficient designs are achieved by using hybrid composites consisting of a combination of high-strength and high-modulus graphite fibers. Typical curves are presented for determining the various mechanical properties of hybrid composites as a function of the amounts and orientations of the constituent materials. To make a realistic assessment of efficiency of hybrid composites as applied to hydrofoil structural components, the various mechanical properties of 0.5-in. thick multilayer, multidirectional hybrid composites are evaluated experimentally. The experimental results for strength and elastic properties of hybrid composites show excellent correlation with predictions and verify the efficiency of these materials as applied to structural components of advanced naval hydrostructures. Preliminary results are also presented on fabrication and testing of a 60-in. long hybrid composite, tapered box beam structure simulating the forward foil on the PCH.