日本複合材料学会誌
Online ISSN : 1884-8559
Print ISSN : 0385-2563
ISSN-L : 0385-2563
30 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
  • 岩堀 豊, 石渡 伸, 石川 隆司
    2004 年 30 巻 6 号 p. 219-226
    発行日: 2004/11/15
    公開日: 2009/08/11
    ジャーナル フリー
    Static strength tests were carried out for the CNF/epoxy two phase composites and CF/CNF/ epoxy three phase laminates in tension, compression, and flexure. The used CNF was cup-stacked type carbon nanofiber (CSNF) made by GSI Creos Corporation. Two different lengths of CSNF dispersed epoxy were employed. Moreover, each CSNF was dispersed to epoxy resin with the ratio of 5-wt% and 10-wt% respectively. An epoxy resin EP827® and a hardener of aromatic amine EPIKURE W® (Japan Epoxy Resin Co. Ltd.) are also employed. TORAYCA® C6343 was employed as reinforcement of three phase laminates. The obtained mechanical properties were compared with the neat epoxy and conventional CFRP laminates. It is revealed that the present three phase laminates exhibit higher compressive and flexural strengths than conventional CFRP laminates. However, dispersion of the CSNF to epoxy may not affect modulus and strengths of the three phase laminates in tensile loading. In CSNF/epoxy composites, there is a trend that increase in CSNF weight makes higher modulus and strengths. It can be concluded that a potential of CSNF as the modifier agent of epoxy for higher mechanical properties is demonstrated in CSNF/epoxy composites and compressive strengths of three phase laminates.
  • 関根 英樹, 白畑 洋, 松田 真理子
    2004 年 30 巻 6 号 p. 227-235
    発行日: 2004/11/15
    公開日: 2009/08/11
    ジャーナル フリー
    In this paper the vibration characteristics of rectangular, symmetric composite sandwich plates and the layup optimization of their laminated FRP composite faces are examined. The honeycomb core is modeled as a thick plate whose transverse shear deformation is taken into consideration based on a higher-order shear deformation theory, and the top and bottom FRP faces are modeled as a very thin sheet. A two-dimensional finite element method is developed using an eight-node isoparametric element. First, the fundamental frequency of the composite sandwich plate is discussed in the subspace of four in-plane lamination parameters of the FRP face. Next, the layup optimization of the FRP face for maximizing the fundamental frequency of the composite sandwich plate is performed by a nonlinear mathematical programming method, and the optimum laminate configuration of the FRP face is determined.
  • 大窪 和也, 藤井 透, 島 和洋
    2004 年 30 巻 6 号 p. 236-242
    発行日: 2004/11/15
    公開日: 2009/08/11
    ジャーナル フリー
    Tensile strength of polypropylene composites reinforced with a natural jute fiber having different chopped lengths and surface treatment was measured. Three kinds of fiber treatments were applied to change the interfacial strength between fiber and matrix. The fragmentation test was also conducted with single jute fiber to determine the interfacial shear strength quantitatively. In situ micro observations of the fracture progress were carried out for single fiber notched specimens under tensile loading. It was found that there is the most effective interfacial strength to improve the tensile strength, nevertheless a few change is observed in fiber strength due to the treatment. For an interfacial strength lower than that of the most effective value, an interfacial debonding led a fatal failure of the composite. In opposite, for an interfacial strength higher than that, the fiber broke down at front of crack tip before the crack reached to the jute fiber. The most effective interfacial strength was shifted to higher value according to the shortening of fiber length. The opitimum state of the composite strength would be obtained by a combination of a low interfacial shear strength long and a low strength jute fibers. This result was explained with the applied stress to the fiber at interfacial failure calculated with the energy release ratio.
  • 越智 昭公, 杉本 健一, 仲井 朝美, 濱田 泰以
    2004 年 30 巻 6 号 p. 243-253
    発行日: 2004/11/15
    公開日: 2009/08/11
    ジャーナル フリー
    In this paper, the effect of stacking sequence and laminate thickness on mechanical behavior of matrix hybrid composite with mechanical joint was investigated to improve the performance of composite structure. Four types of stacking sequences of matrix hybrid and two kinds of laminate thickness were applied. The failure maximum load and the final failure aspect depended on the characteristic of matrix resin and the laminate thickness. The normalized failure maximum load by the laminate thickness was increased and the normalized initial failure load by the laminate thickness was decreased with increase in laminate thickness for respective stacking sequences. The optimum stacking sequence is expected to be that the rigid and the flexible resins are placed at inner and outer domain, respectively.
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