Energy Absorptive Resin Materials for Undersea Structure radiated Noise Reduction

1Fiber reinforced plastic (FRP) materials are used to produce lightweight, high strength hull structures, propulsors, and equipment foundation. All of these undersea structures are required to be energy absorptive. FRP materials offer significantly increased energy absorption with respect to conventional materials used in these applications. Innovative technology is needed to formulate FRP resins that will effectively reduce acoustic transmissions within this type of construction. Hybrid resin systems, such as polyurethane-polyester, urethane-acrylate, rubber modified resins, and thermoplastic fiber/thermoset resin combinations, provide the potential for high acoustic damping and will be evaluated in this research program. The prime focus of this work will be the development of high strength resin systems based on existing technology that will reduce radiated noise in undersea structures. These resin formulations will be evaluated using proven energy absorption design approaches for FRP laminates, which can reduce acoustic emissions in undersea structures without degrading structural efficiency. A test program is defined to evaluate the acoustic transmission levels, over a frequency range of 100 Hz to 4000 Hz, and the structural properties of the FRP laminates. Structural Composites, Inc. (SCI) is uniquely qualified and possesses all of the capability in-house to perform this work, with the exception of specialized test equipment that must be used. Our successful experience, our interactive relationship with the resin and materials manufacturers, and our innovative approach to the problem make SCI the most promising key to a solution.