CNT-Enhanced Mid-Frequency Sonar Dome

Sonar domes provide protection to sonar arrays by imposing a physical barrier to eroding fluid flow as well as preventing incidental impact. Furthermore, they provide aerodynamic shapes over the pressure hull to minimize drag and turbulence. Traditionally, they are fabricated of fiber reinforced polymers (FRP), since composites have superior specific strength and stiffness, are inherently resistant to corrosion and fatigue, and large sections can be molded in a single parts. Fiber and matrix are selected to closely match acoustic impedance with the surrounding sea-water for most efficient sonar performance. Now that glass reinforced plastic (GRP) sonar domes have been proven for mid-frequency surface combatant applications, the Navy is seeking advanced materials that can improve acquisition and maintenance costs, mechanical robustness, and acoustical performance. Thus, Metis Design Corporation (MDC) is proposing the introduction of aligned carbon nanotubes (CNT) into composite sonar domes. CNT have the ability to greatly improve impact resistance while allowing the reduction in cross-sectional thickness, thus reducing manufacturing costs. Furthermore, with their mechanical improvements they allow the potential for using a lower density and/or modulus host composite system, thus lowering acoustic impedance. MDC will partner with Goodrich EPP who manufactures several Navy sonar domes for evaluating material performance.