NASA Scientific and Technical Aerospace Reports

properties of these materials in tension as well. The SAC’s which are defined as the slope of the normalized change in
ultrasonic ‘natural’ velocity as a function of stress were measured in a unidirectional laminate of T300/5208 graphite/epoxy.
Tensile load was applied along the fiber axis with the ultrasonic waves propagating perpendicular to the fiber direction.
Changes in velocity were measured using a pulsed phase locked loop ultrasonic interferometer with the nominal frequency
of the ultrasonic waves being 2.25 MHz.
Author
Graphite-Epoxy Composites; Tensile Stress; Mechanical Properties; Acoustic Measurement
20040121127 NASA Glenn Research Center, Cleveland, OH, USA
Mechanical Behaviour of Woven Graphite/Polyimide Composites with Medium and High Modulus Graphite Fibers
Subjected to Biaxial Shear Dominated Loads
Kumose, M.; Gentz, M.; Rupnowski, P.; Armentrout, D.; Kumosa, L.; Shin, E.; Sutter, J. K.; [2003]; 10 pp.; In English; 14th
International Conference on Composite Materials, 14-18 Jul. 2003, San Diego, CA, USA
Contract(s)/Grant(s): F49620-00-1-0159; NSF CMS-99-77735; 708-31-16
Report No.(s): Paper 1493; No Copyright; Avail: CASI; A02, Hardcopy
A major limitation of woven fiber/polymer matrix composite systems is the inability of these materials to resist
intralaminar and interlaminar damage initiation and propagation under shear-dominated biaxial loading conditions. There are
numerous shear test methods for woven fabric composites, each with its own advantages and disadvantages. Two techniques,
which show much potential, are the Iosipescu shear and +/- 45 deg tensile tests. In this paper, the application of these two tests
for the room and high temperature failure analyses of woven graphite/polyimide composites is briefly evaluated. In particular,
visco-elastic micro, meso, and macro-stress distributions in a woven eight harness satin (8HS) T650/PMR-15 composite
subjected to these two tests are presented and their effect on the failure process of the composite is evaluated. Subsequently,
the application of the Iosipescu tests to the failure analysis of woven composites with medium (T650) and high (M40J and
M60J) modulus graphite fibers and PMR-15 and PMR-II-50 polyimide resins is discussed. The composites were tested
as-supplied and after thermal conditioning. The effect of temperature and thermal conditioning on the initiation of intralaminar
damage and the shear strength of the composites was established.
Author
Woven Composites; Graphite-Polyimide Composites; Shear Stress; Tensile Tests; Failure Analysis
25
INORGANIC, ORGANIC AND PHYSICAL CHEMISTRY
Includes the analysis, synthesis, and use of inorganic and organic compounds; combustion theory; electrochemistry; and
photochemistry. For related information see category 34 Fluid Dynamics and Thermodynamics. For astrochemistry see category 90
Astrophysics.
20040111125 Savannah River Ecology Lab., Aiken, SC, USA
Improved MK42 Melting Model
Tudor, A. A.; Nomm, E.; Mar. 1982; 18 pp.; In English
Report No.(s): DE2004-787810; DPST-82-443; No Copyright; Avail: Department of Energy Information Bridge
An improved Mark 42 melting model has been defined for establishing confinement protection limits (CPLs). This report
describes the new melting model and its application in computing CPLs.
NTIS
Melting; Confinement; Protection
20040111183 Lockheed Martin Corp., Syracuse, NY, USA
Effect of Corrosion Film Composition and Structure on the Corrosion Kinetics of Ni-Cr-Fe Alloys in High Temperature
Water
Rosecrans, P. M.; Lewis, N.; Duquette, D. J.; Feb. 2002; 40 pp.; In English
Report No.(s): DE2004-821696; LM-02K005; No Copyright; Avail: Department of Energy Information Bridge
Nickel alloys such as Alloy 600 undergo Stress Corrosion Cracking (SCC) in pure water at temperatures between about
260 C and the critical point. Increasing the level of Cr in Ni-Fe-Cr alloys increases SCC resistance in aerated and deaerated
water. The mechanism is not understood. The effect of Cr composition on oxide microstructure and corrosion kinetics of
Ni-Fe-Cr alloys was determined experimentally, to evaluate whether the anodic dissolution model for SCC can account for
64