Development of Materials for Load bearing Sonar Windows

New better performing, high modulus, acoustic windows are required by the Navy for the DD(X ) and other programs. The new window materials requirements are strength, high modulus, low lossiness, inert, and acoustically well matched with seawater. The proposed new materials will be developed using commercial of the shelf (COTS) raw materials, inexpensive, and easy to fabricate, resulting in significant cost savings in initial cost and supportability. The proposed new load bearing syntactic materials will be tailored to match both the density and sound speed transmission properties of water. The most viable candidates will be based upon highly halogenated precursors. In order to accomplish this TRI/Austin will use a rational experimental design approach to methodically screen syntactic compositions. The compositions will be screened using ASTM mechanical property, density tests, and ultrasonics for sound speed. Panels will be prepared at the conclusion of the Phase I and tested for sound speed and insertion loss as a function of frequency. The option period involves additional formulation optimization and testing, including the production of additional panels, and information on the reflectivity and shear sound speed of the two best panels, as a function of frequency and incidence angle. BENEFITS: While the primary application of the new sonar window materials is for the DDX, supplementary applications include a variety of Naval vessels. These new window materials can be used in the production of new load bearing rigid castable plastics with broadly adjustable acoustic properties.