Accession Number : ADA097089


Title :   High-Pressure Viewports for Infrared Systems. Phase 1. Germanium


Descriptive Note : Final rept. Oct 1979-Sep 1980


Corporate Author : NAVAL OCEAN SYSTEMS CENTER SAN DIEGO CA


Personal Author(s) : Stachiw, Jerry D


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a097089.pdf


Report Date : Sep 1980


Pagination or Media Count : 122


Abstract : Spherical sectors fabricated from polycrystalline germanium can serve successfully as pressure-resistant windows in IR systems in the marine environment. Spherical sectors and included spherical angle withstood 100 pressure cycles from 0 to 20000 psi without cracking when tested hydrostatically in a compliant metallic mounting with an inclined seat protected by elastomeric gaskets. Nylon cloth-reinforced Neoprene and Kevlar-49-reinforced epoxy gaskets performed successfully provided that the bearing stress did not exceed 20000 psi for Neoprene and 60000 psi for epoxy gaskets. The average flexural and compressive short-term strengths of germanium under uniaxial loading were found to be in the 70000-to-15000-psi ranges, respectively. Germanium also exhibits static fatigue under sustained flexure loading in the marine environment. The static fatigue limit for sustained loading of 1000-hour duration in a seawater environment was found to be in the 8000-to-10000-psi range. Germanium was found to also to exhibit the Kaiser effect even though it is only a rather weak emitter of acoustic emissions under compressive loading. It appears that recording of acoustic emissions during a structural proof test could be incorporated into the quality assurance program for germanium lenses and windows where it would complement visual inspection for the presence of incipient cracks.


Descriptors :   *MECHANICAL PROPERTIES , *HIGH PRESSURE , *INFRARED RADIATION , *GERMANIUM COMPOUNDS , *INFRARED WINDOWS , STRESSES , LOADS(FORCES) , CRACKS , FATIGUE(MECHANICS) , EMITTERS , OCEAN ENVIRONMENTS , NEOPRENE , POLYCRYSTALLINE , COMPRESSIVE PROPERTIES , FLEXURAL PROPERTIES , STATICS , EPOXY COMPOUNDS , QUALITY ASSURANCE , STRENGTH(MECHANICS) , NYLON , ELASTOMERS , FABRICATION


Subject Categories : Plastics
      Infrared Detection and Detectors
      Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE