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Finger Materials for Air Cushion Vehicles. Volume 2. Base Fabrics for Finger Materials.

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Rept. for Oct 77-Mar 79, Feb 80-Aug 82,

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Since the short lifetimes of sealskirt systems on surface effect vehicles SEVs severely limit the long-term serviceability on such craft. A systematic study was undertaken to evaluate the effects of fabric structure on the performance of rubberfabric skirt materials under conditions of high speed, high-curvature flexing. A series of nylon fabrics was designed and manufactured in which the fiber denier, yarn denier, yarn twist, yarn crimp, weave pattern and float length were varied, but in which the tensile strength was kept constant throughout. Each one of the fabrics was rubber-coated using the same natural rubberpolybutadiene blend and the same coating technique. A flex-testing apparatus was designed and built for flexing the rubberfabric composite materials in air at an average radius of curvature of 0.28 in. at a cycling frequency of 15 Hz. The lifetimes in flex of the experimental series of fabrics, as indicated by the appearance of flex cracks in the rubber layer, ranged from a low of 140,000 cycles to a high of 21.7 million cycles, a range of over two orders of magnitude. Factorial analysis of the test results showed that lower yarn denier, lower yarn crimp, and shorter float length plain weave in the fabric substrate offer significant advantages in the ability of the fabric to withstand flexing. Design of three broad fabrics for full-scale skirt trials on the SRN4 craft is described. Originator-supplied keywords include Flex-fatigue, Tear strength, Peel strength, and Flexural rigidity.

Subject Categories:

  • Textiles
  • Elastomers and Rubber
  • Surface Effect Vehicles and Amphibious Vehicles

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