HIGH FREQUENCY SONAR WINDOWS

SONAR WINDOWS BASED UPON GLASS-REINFORCED EPOXY COMPOSITES CURRENTLY SHOW UNSATISFACTORY PERFORMANCE IN ARCTIC ENVIRONMENTS AS A RESULT OF HIGH ACOUSTIC INSERTION LOSSES AND SUSCEPTIBILITY TO DAMAGE UPON IMPACT OR ICE LOADING. FOSTER-MILLER PROPOSES TO INVESTIGATE NEW ACOUSTIC MATERIALS THAT WILL ENABLE NEW COMPOSITE WINDOW DESIGNS TO SATISFY BOTH THE ACOUSTIC AND IMPACT STRENGTH DEMANDS. WE WILL USE OUR EXPERIENCE IN UNDERSEA ACOUSTIC MATERIALS, INNOVATIVE POLYMERS, AND COMPOSITE MATERIAL DESIGN TO PROVIDE THE NAVY WITH A COMPLETE EVALUATION OF KEY TECHNICAL ISSUES, INCLUDING: MATCHING ACOUSTIC IMPEDANCE, REDUCING SELF-GENERATED NOISE IN THE WINDOW, REDUCING ABSORPTION AT SONAR FREQUENCIES DUE TO COMPOSITE CONSTRUCTION, IMPROVING IMPACT RESISTANCE THROUGH RESIN TOUGHNESS AND FIBER STRENGTH, IMPROVING RESISTANCE TO THE UNDERSEA ENVIRONMENT AND RAPID TEMPERATURE CHANGES, AND REDUCING PRODUCTION AND IMPLEMENTATION COSTS. IN PHASE I WE WILL SURVEY THE ACOUSTIC AND MECHANICAL PROPERTIES OF FIBER REINFORCED POLYMERS, WITH SPECIAL EMPHASIS ON INNOVATIVE ACOUSTICALLY TRANSPARENT MATERIALS SUCH AS FLUOROPOLYMERS AND SILICONES. WE WILL ALSO EVALUATE INNOVATIVE, LAYERED COMPOSITES WITH GRADIENT PROPERTIES THAT OVERCOME THE DEFICIENCIES IN CURRENT DESIGNS. IN PHASE II, WE WILL REFINE THE PROCESS, PREPARE COMPOSITE SPECIMENS AND CONDUCT EXTENSIVE TESTING TO QUALIFY OUR INNOVATIVE COMPOSITE DESIGN FOR USE IN NAVY SUBMARINE SONAR WINDOWS. PROCUREMENT SPECIFICATIONS REQUIRED FOR THE PHASE III PROCUREMENT SOLICITATION WILL BE PRODUCED IN PHASE II.