Kazak Composites and our subcontractor ITT propose to advance the design of towed array hose by means of engineered materials and KaZaKs expertise in pultrusion technology. The materials and designs to be developed will have synergistic effects on both buoyancy and strumming suppression. Buoyancy will be improved by adding new high-strength microspheres which also will prevent noise due to collapse. Strumming will be addressed by investigating several approaches, including a specially designed conformal layer not increasing the straight line drag coefficient or interfering with the array handling gear. This approach permits use of stochastic techniques in design, to prevent formation of coherent wake structures at several scales. An alternative approach is the use of negative Poisson ratio material to change the sectional shape of the hose in a turn. We also propose a novel reinforcement configured to prevent crimping of the hose cross-section under bending, as well as milking of the hose under longitudinal drag forces, while maintaining desirable longitudinal strength and elongation characteristics. The scope of proposed Phase I work will cover materials trade studies and analysis of designs, as well as static and tunnel tests of representative elements. The outlook for a Phase II is a full-scale prototype.
Benefit: The correction of towed array buoyancy and strumming will lead to lower drag and substantially improved acoustic performance and uptime for the array, maintaining the tactical advantage to the US submarine fleet. In keeping with the recent use of COTS technology for substantially reduced costs of the electronic array proper, KaZaKs efficient pultrusion process can produce an improved hose at low cost. Considering the limited need for replacement of towed array hoses, we estimate the military market as relatively small. Beyond this market, hose pultrusion technology potentially could become a viable alternative for consolidating functions and saving weight in other applications where structural requirements can be combined with fluid handling, such as in terrestrial or flight vehicles. There is also a potentially much larger market in high pressure coilable hose technology for use in the down-hole oil and gas production industry.
Keywords: composite reinforcement, composite reinforcement, microspheres, Pultrusion, Strumming, Drag Reduction, towed array hose, negative Poisson ratio, buoyancy
