Journal of the Japan Society for Composite Materials
Online ISSN : 1884-8559
Print ISSN : 0385-2563
ISSN-L : 0385-2563
Volume 17, Issue 4
Displaying 1-6 of 6 articles from this issue
  • Akimitsu OKURA
    1991 Volume 17 Issue 4 Pages 133-139
    Published: July 15, 1991
    Released on J-STAGE: August 11, 2009
    JOURNAL FREE ACCESS
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  • M. FUJII, N.-S. CHOI, K. TAKAHASHI
    1991 Volume 17 Issue 4 Pages 140-145
    Published: July 15, 1991
    Released on J-STAGE: August 11, 2009
    JOURNAL FREE ACCESS
    Fracture behavior of unfilled (N-PP) and short glass fiber filled polypropylene (GF-PP) has been studied with compact tension specimens by varying annealing temperature and loading rate. The crystallinity measurements and the dynamic mechanical analysis were also carried out. The filled specimens exhibited an increase in the maximum load at a temperature below -30°C, and an increase in the fracture toughness (Jm) in a temperature range between -30°C and 0°C corresponding to the glass transition region of PP. They showed ductile fracture behavior beyond 0°C. The fracture toughness of N-PP exhibited a decrease with increasing loading rate. On the other hand, GF-PP showed little change in the fracture toughness. The annealing of the specimens just below the melting temperature of PP resulted in an increase in the crystallinity and the dynamic modulus. However, it induced a decrease in the maximum load and the fracture toughness.
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  • M. FUJII, N.-S. CHOI, K. TAKAHASHI
    1991 Volume 17 Issue 4 Pages 146-154
    Published: July 15, 1991
    Released on J-STAGE: August 11, 2009
    JOURNAL FREE ACCESS
    Fracture mechanisms of unfilled (N-PP) and short glass fiber filled polypropylene (GF-PP) were studied with particular attention to the effect of temperature and annealing on the fracture morphology. Optical and scanning electron microscope observations were made for fractured compact tension specimens. In a temperature range from -60°C to 23°C, a low speed fracture zone appeared on the fracture surfaces of N-PP. The zone increased in area almost linearly with an increase of logarithmic value of the fracture toughness (Jm). On a surface region near the crack tip of loaded GF-PP specimens, whitening was observed and its area had a linear relation with logarithmic toughness value. The slope of the linearity changed considerably below and above the temperature range of -30°C∼0°C. The glass transition temperature of PP resin was about -15°C. Annealing of N-PP specimens caused a change in propagation mode from a branching type to a straight type, whereas for GF-PP it caused to generate rather flat fracture surfaces.
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  • Z. MAEKAWA, H. HAMADA, A. YOKOYAMA, K. LEE, S. ISHIBASHI
    1991 Volume 17 Issue 4 Pages 155-164
    Published: July 15, 1991
    Released on J-STAGE: August 11, 2009
    JOURNAL FREE ACCESS
    A study was conducted to evaluate reliability of the longitudinal tensile properties of unidirectional CFRP laminates. Four kinds of CFRP were tested in order to examine the factors of variability and have the information concerning reliability improvement. Temperature dependence of the strength and its variability were investigated by means of testing at three kinds of temperatures. Statistical distributions of the respective mechanical properties were obtained from the tensile tests with large sample size. As a result, toughening the matrix resin was proved to increase the strength and improve the reliability of CFRP.
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  • Takashi ISHIKAWA
    1991 Volume 17 Issue 4 Pages 165-169
    Published: July 15, 1991
    Released on J-STAGE: August 11, 2009
    JOURNAL FREE ACCESS
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  • [in Japanese]
    1991 Volume 17 Issue 4 Pages 170
    Published: July 15, 1991
    Released on J-STAGE: August 11, 2009
    JOURNAL FREE ACCESS
    Download PDF (164K)
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