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Volume 23 (1997)
- Issue 6 Pages 199-
- Issue 5 Pages 161-
- Issue 4 Pages 121-
- Issue 3 Pages 81-
- Issue 2 Pages 41-
- Issue 1 Pages 1-
Volume 23, Issue 4
Displaying 1-4 of 4 articles from this issue
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Muneaki YAMAGUCHI, Yuko TANAKA, Katsutoshi TANAKA1997 Volume 23 Issue 4 Pages 121-128
Published: July 15, 1997
Released on J-STAGE: August 11, 2009
JOURNAL FREE ACCESSThe composite materials were made from three multi-functional epoxy resins (EP) cured with five hardeners and filled with aramid (Technora®) short fibers (AFP) by 2.44 wt%. Effects of aging (heat-treated) at 130°C for 5, 000 h and wetting at 21°C for 5, 000 h in distilled water on the dynamic mechanical properties were studied. The morphology of the fiber dispersion in AFP-filled specimens did not change during the aging. Weight of the aged specimens decreased for a prolonged aging time. The maximum decrease during the aging for 5, 000h was 3.5wt%. The glass transition temperature (Tg) of all the specimens shifted to higher temperature by the aging. The dynamic storage moduli (E') of most of aged specimens decreased at lower temperature (-140°C) and room temperature (25°C) compared with those of unaged specimens. At higher temperature (200°C), the moduli of specimens almost increased and in particularly those of the specimens cured with diamines increased significantly. Absorbed water of wet specimens reached a maximum value of 5.0wt%, and values of the specimens cured with diamines were larger than those of the specimens cured with acid anhydrides. The Tgof all the specimens shifted to lower temperature by the absorption of water. E' of many wet specimens increased in the range of lower temperature to room temperature, but E' of all the specimens at higher temperature extremely fell down.View full abstractDownload PDF (3829K) -
Zheng-Wang LI, Isao KIMPARA, Kazuro KAGEYAMA, Toshio SUZUKI, Isamu OHS ...1997 Volume 23 Issue 4 Pages 129-136
Published: July 15, 1997
Released on J-STAGE: August 11, 2009
JOURNAL FREE ACCESSMode II fatigue delamination growth behaviors of toughened unidirectional CF/Epoxy laminates, T800H/3900-2 and IM-600/#134, were characterized. Both GIImax-constant tests and GIImax-shedding tests were conducted by a test system based on CSD measurement. As the results, in the initial period of the delamination growth there exist transient behaviors of the delamination growth rate. The index number of power law of two kinds of toughened CFRP were smaller than that of the untoughened CFRP, T800H/3631. But for the threshold behavior, there was almost no improvement with the toughening. The difference of the mode II delamination behaviors between the toughened CFRP and the untoughened CFRP is related to the thickness of their interlamination and the size of the plastic zone. Moreover, the influence of stress ratio was evaluated by applying equivalent energy release rate range. Discussion are also made on the delamination growth onset determination.View full abstractDownload PDF (9838K) -
Guangjun SUI, Tadashi OHYOSHI, Kimihisa MIURA, Yotsugi SIBUYA1997 Volume 23 Issue 4 Pages 137-143
Published: July 15, 1997
Released on J-STAGE: August 11, 2009
JOURNAL FREE ACCESSDiscussion of elastic wave backscatter from an inhomogeneous layered part of a composite is made with the computational results by using a special layer elements. The stacking of linear inhomogeneous layer element, say LILE, has been certified as an excellent model for the computation of a gradient inhomogeneous layer. Intensity curves of the backscatter calculated as a function of incident wave number are presented in a wide frequency range, and characteristic relations between the inhomogeneous structure and the backscatter intensity are discussed. The results show that some peaks appear on the curves. Study of the characteristic features provides us viable clues for computation to get the information on layering structure and spatial exponential decay of inhomogeneous material constants of composites.View full abstractDownload PDF (901K) -
Masaru ZAKO, Tetsusei KURASHIKI1997 Volume 23 Issue 4 Pages 144-150
Published: July 15, 1997
Released on J-STAGE: August 11, 2009
JOURNAL FREE ACCESSDownload PDF (2112K)
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