Accession Number : ADA024775

Title :   Acrylic Plastic Spherical Shell Windows under Point Impact Loading.

Descriptive Note : Research and development rept. Jun 71-Jun 74,

Corporate Author : NAVAL UNDERSEA CENTER SAN DIEGO CALIF

Personal Author(s) : Stachiw,J. D. ; Burnside,O. H.

Report Date : JUL 1975

Pagination or Media Count : 78

Abstract : Acrylic plastic spherical sector windows have been subjected to point impact loading applied to the convex surface at the center of the window. The point impact loading simulated the velocities and kinetic energies encountered in a typical collision between an immovable underwater obstacle and a submersible equipped with a large panoramic bow window. Experimental results show that spherical sector windows with 117 degrees included angle and t/Ro = 0.094 fracture during simulated underwater collisions where the kinetic energy of the impactor was at least 435 foot-pounds. For windows with t/Ro = 0.166 the required kinetic energy to generate fracture is 1750 foot-pounds. The kinetic energy of a submersible required for initiation of fracture in the bow window increased with depth, but only moderately. Protective shields fabricated from 0.375-inch thick acrylic plastic did not provide any significant protection against impact generated fracture of spherical windows. Only a bumper appears to provide adequate protection for the bow window in a submersible colliding with a large underwater object.

Descriptors :   *UNDERWATER VEHICLES, *IMPACT TESTS, *ACRYLIC RESINS, *WINDOWS, FINITE ELEMENT ANALYSIS, FRACTURE(MECHANICS), IMPACT STRENGTH, KINETIC ENERGY, IMPACT POINT.

Subject Categories : PLASTICS
      MARINE ENGINEERING

Distribution Statement : APPROVED FOR PUBLIC RELEASE

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