NASA Scientific and Technical Aerospace Reports

weapons systems. For reasons arising from the dramatically different length scales associated with those dissipative
mechanisms and the length scales characteristic of the overall structure, this physics cannot be captured adequately through
direct simulation of the contact mechanics within a structural dynamics analysis. The only practical method for
accommodating the nonlinear nature of joint mechanisms within structural dynamic analysis is through constitutive models
employing degrees of freedom natural to the scale of structural dynamics. This document discusses a road-map for developing
such constitutive models.
NTIS
Weapon Systems; Dynamic Structural Analysis; Vibration Damping
20040121083 ATK-Thiokol Propulsion, Brigham City, UT, USA
Development of a Low Data Event Timer for Monitoring an Advancing Crack in Fracture
Macon, D. J.; Totman, P. D.; Bodily, M. L.; Everton, R. L.; Eggett, M. R.; [2004]; 26 pp.; In English; Original contains black
and white illustrations
Contract(s)/Grant(s): NAS8-97238; Copyright; Avail: CASI; A03, Hardcopy
Monitoring the crack position and velocity in a fracture specimen can be difficult and laborious. In addition, the data
storage requirements can be considerable depending upon the testing conditions. A low data event timer was developed to
alleviate these problems. The test apparatus was applied to cantilever beams bonded with a structural epoxy and tested under
different conditions such as stable to unstable transitions and different temperature extremes. The results indicate that the
approach eliminates problems associated with other types of crack measurement and greatly simplifies the measuring process.
Author
Crack Propagation; Fracture Mechanics; Mechanical Properties; Timing Devices; Potentiometers (Instruments)
20040121124 NASA Glenn Research Center, Cleveland, OH, USA
Compliant Foil Seal Investigations
Proctor, Margaret; Delgado, Irebert; [2003]; 22 pp.; In English; 2003 NASA Seal/Secondary Air System Workshop, 5-6 Nov.
2003, Cleveland, OH, USA
Contract(s)/Grant(s): 22-714-09-18; No Copyright; Avail: CASI; A03, Hardcopy
NASA Glenn Research Center has been working with Mohawk Innovative Technology, Inc. (MiTi) to develop a
Compliant Foil Seal for use in gas turbine engines. MiTi was awarded phase I and phase II SBIR contracts to analyze, develop,
and test foil seals. As part of the Phase II contract, MiTi delivered an 8.5 inch diameter foil seal to NASA GRC for testing.
Today I will be presenting some results of testing the 8.5 inch foil seal at NASA.
Author (revised)
Foils (Materials); Seals (Stoppers); Gas Turbine Engines; Engine Parts
42
GEOSCIENCES (GENERAL)
Includes general research topics related to the Earth sciences, and the specific areas of petrology, mineralogy, and general geology. For
other specific topics in geosciences see categories 42 through 48.
20040111989 NASA Marshall Space Flight Center, Huntsville, AL, USA
Microbial Remains in Middle Proterozoic Rocks of Northern Australia
Astafieva, Marina; Rozanov, Alexei Yu.; Hoover, Richard B.; Vickers-Rich, P.; Wilde, A.; [2004]; 1 pp.; In English;
International Society for Optical Science and Technology 49th Annual Meeting and Proceedings, 2-6 Aug. 2004, Denver, CO,
USA; Original contains black and white illustrations; No Copyright; Avail: Other Sources; Abstract Only
Investigation of the samples of the McArthur River complex ore deposit, one of the most zinc-lead mindprovinces in
the world, brings us to conclusion about the possibility of the biogenic origin of sulfides in McArthur River ore deposit and
to make suppositions about the formation of the studied rocks in the photic zone of sea.
Author
Microorganisms; Rocks; Precambrian Period; Minerals; Deposits; Bacteria
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