Journal of the Japan Society for Composite Materials
Online ISSN : 1884-8559
Print ISSN : 0385-2563
ISSN-L : 0385-2563
Volume 33, Issue 3
Displaying 1-6 of 6 articles from this issue
  • Hajime KISHI
    2007 Volume 33 Issue 3 Pages 79-82
    Published: May 15, 2007
    Released on J-STAGE: August 11, 2009
    JOURNAL FREE ACCESS
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  • Jun TAKAHASHI, Kiyoshi UZAWA, Isamu OHSAWA, Akihiko KITANO, Koji YAMAG ...
    2007 Volume 33 Issue 3 Pages 82-86
    Published: May 15, 2007
    Released on J-STAGE: August 11, 2009
    JOURNAL FREE ACCESS
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  • Hideaki MIYAZAWA, Sunao SUGIMOTO, Ning HU, Hisao FUKUNAGA
    2007 Volume 33 Issue 3 Pages 87-94
    Published: May 15, 2007
    Released on J-STAGE: August 11, 2009
    JOURNAL FREE ACCESS
    In this paper, we propose an experimental identification method of location and history of impact forces which act on CFRP composite structures. First, a transfer matrix to relate an impact force to sensor responses is directly constructed from experimentally measured force histories and measured sensor responses. Next, the location and history of the applied force are identified using two steps. In the first step, the force history is evaluated as a solution of a quadratic programming problem by using the transfer matrix and measured strain responses. In the second step, the force location is determined as a location where an error between measured sensor responses and evaluated ones is minimized. By repeating the above two steps, both the true location and the history can be identified. Finally, the present method is applied to three kinds of CF/Epoxy laminated plates and a CF/PEEK stiffened panel, and its validity is verified from the experimental results.
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  • Tetsuo YASUOKA, Yoshinobu SHIMAMURA, Akira TODOROKI
    2007 Volume 33 Issue 3 Pages 95-103
    Published: May 15, 2007
    Released on J-STAGE: August 11, 2009
    JOURNAL FREE ACCESS
    Carbon nanofiller (CNF) has good electrical conductivity. Addition of a few percentages of carbon nanofillers to polymer yields electrical conductivity but hardly affects the mechanical properties of polymer. This conductive polymer may be useful for sensing applications such as strain sensors and chem-resist sensors. Many researchers have reported on the electrical conductivity, but the electrical resistance change under strain of the carbon nanofiller composites is not fully investigated. In this study, the electrical resistance change under strain of CNF/flexible-epoxy composites was investigated experimentally and analytically. Experimental results show that the electrical resistance change under strain is nonlinear and much larger than that in metal, and the electrical resistance change rate decreases as increasing the weight fraction of CNF. The mechanism of the electrical resistance change under strain of CNF/polymer composites was discussed by using electrical circuit simulation based on a percolation network model and tunneling effect between CNFs. The results imply that the nonlinear behavior is caused by the combination of tunneling effect between CNFs and the change of the conductive network, and that the decrease of the electrical resistance change rate with increase of the weight fraction of CNF is caused by the nature of the percolation network.
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  • Hikaru HOSHI, Keisuke NAKANO, Yutaka IWAHORI, Takashi ISHIKAWA, Hirosh ...
    2007 Volume 33 Issue 3 Pages 104-115
    Published: May 15, 2007
    Released on J-STAGE: August 11, 2009
    JOURNAL FREE ACCESS
    Tension and compression tests of scarf joints were conducted to evaluate the effect of angle of scarf. Impact loadings were applied for some specimens prior to the residual compression and tension test of scarf joints. Such scarf joints were experimentally investigated by using three variations of scarf angles of 3, 4.5, and 6 degrees. The impact loadings at the center of the specimen were with two different energy level for tension specimen, and three for compression. As a result, the statical tensile and compressive strengths of non-damaged scarf joint decreased as the scarf angle increased. The strengths of scarf joint compared with the parent specimen are more significantly decreased in tension than in compression. For the small angle of scarf the impact damage and the residual strength of scarf joints were measured to be similar to those of the parent material. Whereas for the large scarf angle, the delamination of the adhesive layer of scarf joint increased remarkably, then, the residual strength of scarf joint decreased. It is obvious that the delamination of adhesive layer affected the residual strength of scarf joints under tension and compression.
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  • Takahira AOKI
    2007 Volume 33 Issue 3 Pages 116-118
    Published: May 15, 2007
    Released on J-STAGE: August 11, 2009
    JOURNAL FREE ACCESS
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