In Phase I GRW showed a Photonics Head made of a neat blend of GRW urethane can survive the combined loading of hydrostatic pressure and an underwater shock. This is based on extensive investigation of the mechanical properties of urethane blends, extrapolation of stress strain results (to be finalized at the completion of Phase I) using a fluid/structure nonlinear FEA with an attachment ring redesign, and GRW's manufacturing procedure. The manufacturing procedure was applied to the casting of a Head-sized cylinder, made from an optimum blend, that tensile tests showed maintained uniform mechanical properties throughout. GRW is currently doing further development of both neat and random fiber composite urethanes to achieve the necessary material selection for Phase II. In Phase II GRW will continue selection of optimum urethane materials that meet the design loading criteria of the Heads/Housings. Tests to establish the strain rate dependency of the materials will be performed and the results employed in ETC's FEA model. Modifications to mixing machines will be made as necessary to manufacture composite Heads/Housings.
Benefits: The exceptional manufacturing and material cost reduction of a neat (or reinforced) urethane to replace high strength, shock resistant parts in a marine environment will create a military and commercial demand for additional Heads/Housings, Masts, Transducer Housings, Hull Plates and Gratings, as well as commercial bumper parts and machinery.
Keywords: Masts Urethane Underwater Shock High Strength Heads
