Journal of the Japan Society for Composite Materials
Online ISSN : 1884-8559
Print ISSN : 0385-2563
ISSN-L : 0385-2563
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Volume 33, Issue 2
Displaying 1-5 of 5 articles from this issue
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  • [title in Japanese]
    Goichi BEN, Hiroyuki HAMADA, Kyousuke HAKKAKU, Yoshio AOKI, Asami NAKA ...
    2007 Volume 33 Issue 2 Pages 41-47
    Published: March 15, 2007
    Released on J-STAGE: August 11, 2009
    DOIhttps://doi.org/10.6089/jscm.33.41
    JOURNAL FREE ACCESS
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  • Torsional Behavior of Unidirectional CFRP and GFRP
    Keiji ONTA, Toshio OGASAWARA, Tomohiro YOKOZEKI, Shinji OGIHARA
    2007 Volume 33 Issue 2 Pages 48-54
    Published: March 15, 2007
    Released on J-STAGE: August 11, 2009
    DOIhttps://doi.org/10.6089/jscm.33.48
    JOURNAL FREE ACCESS
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    The helicopter bearingless rotor flexbeam is usually made of glass-fiber reinforced plastic composite (GFRP). For improving performance and reliability as well as the reduction of maintenance cost and weight, CFRP is expected to be applied to the flexbeam of the rotor system in future. However, few researches regarding torsion behavior of unidirectional CFRP have been made. In this study, torsion behavior of unidirectional CFRP and GFRP was examined in detail. A two-axis tension/ torsion examination device was used to observe torsion behavior of CFRP and GFRP. It was confirmed that the behavior of such materials is comprised of linearity/non-linearity domains. In addition, off-axis tension tests were performed in order to explain a non-linear behavior with a one-parameter plasticity model proposed by Sun et al., and a plasticity parameter for each of the materials was obtained. A prediction of a linear/non-linear behavior also became possible by incorporating the 3-D plasticity model into an FEM analysis with the estimated plastic parameters. The torsional rigidities of CFRP and GFRP are almost the same. This suggests that GFRP can be replaced by CFRP as torsional elements of a helicopter flex beam without an increase in torsion torque of the rotor system.
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  • Impact Resistance of Interleaved FRP Using Non-Woven Fabric as Interleaf Materials
    Manabu KUWATA, Satoshi MATSUDA, Hajime KISHI, Atsushi MURAKAMI, Paul J ...
    2007 Volume 33 Issue 2 Pages 55-61
    Published: March 15, 2007
    Released on J-STAGE: August 11, 2009
    DOIhttps://doi.org/10.6089/jscm.33.55
    JOURNAL FREE ACCESS
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    The vacuum assisted resin transfer molding process (VaRTM) is a lower-cost molding method than autoclave molding, and therefore the VaRTM method is preferred for use with structural composites molding. On the other hand, interleaf technology is known as an effective method for improving impact resistance for composite laminates. However, it is impossible to exploit polymer films as interleaf materials when using the VaRTM processing method as resin impregnation in the thickness direction is prevented by the interleaf films. To overcome this problem, the focus of this study was to use non-woven fabric as interleaf materials that were compatible with the VaRTM method and to evaluate their performance. The rate of impregnation by resin for non-interleaved and interleaved FRP was similar. Impact resistance for interleaved FRP had improved by interleaving non-woven fabric. The polyamide non-woven fabric used as interleaves in FRP suppressed crack propagation in the interlaminar region. It is believed that the degree of adhesion of the fabric to the matrix resin is an important factor on the suppression of crack propagation.
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  • Heat Resistant Polymer Composites with Tg-less Epoxy Resin
    Hirofumi NISHIDA, Norio HIRAYAMA, Satoshi MATSUDA, Hajime KISHI, Atsus ...
    2007 Volume 33 Issue 2 Pages 62-71
    Published: March 15, 2007
    Released on J-STAGE: August 11, 2009
    DOIhttps://doi.org/10.6089/jscm.33.62
    JOURNAL FREE ACCESS
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    This study includes the development of a high heat-resistant FRP whose matrix is Tg-less epoxy resin which can be cured by anionic polymerization with potassium carboxylate salts as initiators. First, various epoxy resins with different chemical structures were evaluated to find an epoxy resin composition which has the least decrease in elastic modulus even at an elevated temperature. As a result, R, which is defined as the ratio of the modulus at 250°C to that at 25°C, exhibited the highest value of 44.5% in the combination of bisphenol A type epoxy resin with a multi-functional glycidyl ether derived from multi-functional phenols. The GFRP whose matrix was this Tg-less epoxy resin composition exhibited high heat-resistant property of R≥80% at 34 vol% of glass fiber content. The FRP had also excellent corrosion-resistance because the chemical structure of its matrix is hard to be hydrolyzed even under acidic or alkaline conditions.
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  • [title in Japanese]
    Zhishen WU, Kentaro IWASHITA, Keiji HAYASHI, Tetsuo HGUCHI, Shinkichi ...
    2007 Volume 33 Issue 2 Pages 72-75
    Published: March 15, 2007
    Released on J-STAGE: August 11, 2009
    DOIhttps://doi.org/10.6089/jscm.33.72
    JOURNAL FREE ACCESS
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