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Record Details

Record 94 of 18660
Residual stress in high modulus carbon fibers
Author and Affiliation:
Chen, K. J.(Rensselaer Polytechnic Inst., Troy, NY, United States)
Diefendorf, R. J.(Rensselaer Polytechnic, Institute, Troy, NY, United States)
Abstract: The modulus and residual strain in carbon fibers are measured by successively electrochemically milling away the fiber surface. Electrochemical etching is found to remove the carbon fiber surface very uniformly, in contrast to air and wet oxidation. The precision of fiber diameter measurements is improved by using a laser diffraction technique instead of optical methods. More precise diameter measurements reveal that past correlations of diameter and fiber modulus are largely measurement artifact. The moduli of most carbon fibers decrease after the outer layers of the fibers are removed. Owing to experimental difficulties, the moduli and strengths of the fibers at their centers are not determined, and moduli are estimated on the basis of microstructure. The calculated residual stresses are found to be insensitive to these moduli estimates as well as the exact form of regression equation used to describe the moduli and residual strain distributions. Axial compressive residual stresses are found to be very high for some higher modulus carbon fibers. It is pointed out that the compressive stress makes the fibers insensitive to surface flaws when loaded in tension but it may initiate failure by buckling when loaded in compression.
Publication Date: Jan 01, 1982
Document ID:
19830058916
(Acquired Nov 30, 1995)
Accession Number: 83A40134
Subject Category: COMPOSITE MATERIALS
Document Type: Conference Paper
Publication Information: (SEE A83-40126 18-24)
Publisher Information: Japan
Meeting Information: Progress in science and engineering of composites; Fourth International Conference on Composite Materials; October 25-28, 1982; Tokyo; Japan
Meeting Sponsor: Direction des Marerials
Contract/Grant/Task Num: NGL-33-018-003
Financial Sponsor: NASA; United States
Organization Source: Rensselaer Polytechnic Inst.; Troy, NY, United States
Description: 9p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: CARBON FIBERS; FIBER STRENGTH; RESIDUAL STRESS; STRESS ANALYSIS; AXIAL STRESS; DIAMETERS; ELECTRON MICROSCOPY; ETCHING; LASER OUTPUTS; OPTICAL MICROSCOPES; STRAIN DISTRIBUTION; WAVE DIFFRACTION
Imprint And Other Notes: IN: Progress in science and engineering of composites; Proceedings of the Fourth International Conference on Composite Materials, Tokyo, Japan, October 25-28, 1982. Volume 1 (A83-40126 18-24). Tokyo/Amsterdam, Japan Society for Composite Materials/North-Holland, 1982, p. 97-105. Research supported by the Boeing Co. and U.S. Air Force.
Availability Source: Other Sources
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