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Volume 20 (1994)
- Issue 6 Pages 215-
- Issue 5 Pages 173-
- Issue 4 Pages 131-
- Issue 3 Pages 91-
- Issue 2 Pages 57-
- Issue 1 Pages 1-
Volume 20, Issue 5
Displaying 1-5 of 5 articles from this issue
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Hiroshi TANAKA1994 Volume 20 Issue 5 Pages 173-177
Published: October 15, 1994
Released on J-STAGE: August 11, 2009
JOURNAL FREE ACCESSDownload PDF (1881K) -
R. TANAHASHI1994 Volume 20 Issue 5 Pages 178-186
Published: October 15, 1994
Released on J-STAGE: August 11, 2009
JOURNAL FREE ACCESSThe use of dissimilar materials and the design of rigidity distribution are effective in improving the performance of skis. The complication of the composite structures makes it extremely difficult to apply the generally known Saint Venant's torsion theory to skis. Therefore, an approximate calculation method derived from the theory of the thin-walled close structure is proposed as a calculation method of solving a complicated structural problem instead of using Saint Venant's torsion theory. The calculation method is applicable to the structure composed of the multiple high-elasticity layer skins and a low-elasticity core. Then, six different experiments were conducted on a simplified model and skis to prove the usefulness of the formula. As a result, this formula was proved to be useful enough. Thus, the conventional trial-anderror method of research and development has been improvement greatly.View full abstractDownload PDF (6897K) -
E. HAYAKAWA, M. SHIOYA, T. SAITOH, A. TAKAKU1994 Volume 20 Issue 5 Pages 187-194
Published: October 15, 1994
Released on J-STAGE: August 11, 2009
JOURNAL FREE ACCESSAn apparatus measuring the compressive behavior of single fibers in the transverse direction conveniently with sufficient accuracy was developed. In this apparatus, a single fiber was compressed between two glass plates, and the compressive displacement of the fiber was determined by applying the optical interference occurring between the two glass plates. By using this apparatus, the compressive behavior of a series of PAN-based and pitch-based carbon fibers were investigated, and the following features were ascertained : 1) carbon fibers can be deformed reversibly by the transverse compression up to a displacement corresponding to about 10% of diameter ; 2) as the fiber is compressed in the transverse direction, the compressive deformation becomes more difficult for PAN-based carbon fibers, while for pitch-based carbon fibers, the compressive deformation becomes easier; 3) the transverse modulus tends to decrease with increasing crystallite orientation to the fiber axis direction. The experimentally observed relationship between the transverse modulus and the crystallite orientation can not be explained by the fiber structure models assuming that uniform stress or uniform strain is applied to the crystallites randomly distributed in a fiber cross-section. This suggests that the transverse modulus changes dependently on the fiber texture composed of crystallite aggregates. The transverse compressive strength of pitch-based carbon fibers decreased with increasing crystallite orientation. The SEM photographs of the fractured fibers are shown.View full abstractDownload PDF (6714K) -
T. SHIMOKAWA, Y. HAMAGUCHI, Y. KAKUTA, S. SANBONGI, Y. MORINO, M. YAMA ...1994 Volume 20 Issue 5 Pages 195-204
Published: October 15, 1994
Released on J-STAGE: August 11, 2009
JOURNAL FREE ACCESSThe objective of this study is to statistically evaluate tensile mechanical properties of two kinds of carbon/polyimide composites, i.e., Celion 6K/PMR-15 and T800H/PMR-15 with a quasi-isotropic stacking sequence. Tensile tests were conducted under room temperature using about thirty smooth specimens each. Mechanical properties measured are ultimate strength, failure strain, elastic modulus, and Poisson's ratio. Statistical analyses use four kinds of distribution models such as normal, log-normal, type-I extreme-value, and two-parameter Weibull distributions. These analyses derive the estimates of central tendencies and scatter parameters, and B allowables. Moreover, the modified Kolmogorov-Smirnov goodness-of-fit test for the four kinds of distribution models is applied for the data of each mechanical property. Correlation between mutual mechanical properties is examined, and a multiple regression analysis applied to predict the ultimate strength.View full abstractDownload PDF (1192K) -
[in Japanese]1994 Volume 20 Issue 5 Pages 214
Published: October 15, 1994
Released on J-STAGE: August 11, 2009
JOURNAL FREE ACCESSDownload PDF (174K)
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