日本複合材料学会誌
Online ISSN : 1884-8559
Print ISSN : 0385-2563
ISSN-L : 0385-2563
37 巻, 6 号
選択された号の論文の4件中1~4を表示しています
研究論文
  • 加藤木 秀章, 島村 佳伸, 東郷 敬一郎, 藤井 朋之
    2011 年 37 巻 6 号 p. 203-208
    発行日: 2011年
    公開日: 2012/04/05
    ジャーナル フリー
    Natural fiber reinforced plastics have been expected as alternative materials of glass fiber reinforced composites. The fatigue properties of natural fiber reinforced plastics are, however, not always well known. In this study, uniaxial tensile fatigue tests of unidirectional jute spun yarn reinforced polylactic acid (PLA) were conducted in order to clarify the fatigue strength and its mechanism. The fatigue strength decreased with increasing the number of cycles. The fatigue strength at 106 cycles was 55% of the ultimate strength. The fatigue failure of composite specimens was probably caused by the breakage of the jute filaments of spun yarn at the tips of fatigue cracks in PLA. This implies that the fatigue strength of the composite was strongly affected by the fatigue property of PLA.
  • 鮑 力民, 赤羽 賢一, 施 建, 剱持 潔
    2011 年 37 巻 6 号 p. 209-215
    発行日: 2011年
    公開日: 2012/04/05
    ジャーナル フリー
    A system that detects FRP erosion automatically is important. To achieve such a system, an FRP erosion detecting sensor using on optical fiber was proposed in this study. The relationship between the erosion characteristics of optical fiber alone and the attenuation of light was investigated, and it was found that such relationship can be applied in an erosion-detecting sensor. The sensor feasibility was confirmed by investigating the erosion characteristics of FRP with optical fiber embedded and conducting tests to detect abrasion based on the light attenuation. Four point bending tests were conducted on an FRP laminated plate with embedded optical fiber, and the mechanical characteristics of the plate were examined. The results indicated that the embedding optical fiber did not degrade the FRP rupture strength. The proposed erosion monitoring system effectively predicts FRP erosion.
  • 鹿島 彰浩, 小柳 潤, 荻原 慎二
    2011 年 37 巻 6 号 p. 216-225
    発行日: 2011年
    公開日: 2012/04/05
    ジャーナル フリー
    This paper evaluates interfacial failure criterion under combined stress state and precise location along the fiber circumference of interfacial failure (debonding) initiation at glass fiber fiber/epoxy interface by the cruciform specimen method. The effects of both thermal residual stress occurred during specimen preparation and inelastic stress-strain constitutive relationship of matrix resin on the evaluation of interfacial failure criterion are considered. The interfacial stresses distribute along with fiber circumference. In this study, the location of interfacial failure initiation is specified and the interfacial failure criterion is evaluated. By changing the cruciform arm angle (the angle between the fiber and the loading directions), various combined stress states are obtained which make it possible to evaluate the interfacial failure criterion. Both the quadratic and parabolic criteria are assumed and discussed.
  • 黄木 景二, 田中 孝明
    2011 年 37 巻 6 号 p. 226-233
    発行日: 2011年
    公開日: 2012/04/05
    ジャーナル フリー
    This paper presents electrical resistance change due to moisture in a CFRP cross-ply laminate with and without matrix cracking. First, the electrical resistance change was measured for wet unidirectional and cross-ply laminates at room temperature and below the freezing point. Next, an equivalent circuit model was proposed for the cross-ply laminate, taking the resistance change ascribed to matrix cracking into account. It was found that resistance characteristics of the intact cross-ply laminate were similar to those of the longitudinal ply. Resistance properties of the wet cross-ply laminate with matrix cracking were dominated by those of the longitudinal ply, while the resistance change of the dry cracked cross-ply laminate was affected by the matrix crack resistance. The resistance of the dry cracked laminate decreases below the freezing point. Contrarily, the resistance of the wet cracked laminate increases below the freezing point.
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