巻号一覧
40 巻 (2014)
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40 巻, 5 号
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研究論文
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津田 皓正, 仲本 兼悟, 小笠原 俊夫, 文 淑英, 武田 展雄, 小川 武史, 島村 佳伸, 井上 翼2014 年 40 巻 5 号 p. 209-217
発行日: 2014年
公開日: 2015/10/22
ジャーナル フリーThe objective of this study is evaluating the effect of stretching on the angular orientation of carbon nanotubes (CNT) and the mechanical properties of aligned CNT/epoxy composites. Stretching tests were conducted by tensile testing after fabricating prepregs with stretch ratios of 0%, 2%, 5%, 10% and 18%, respectively. Microscopic observations by scanning electron microscope (SEM) were carried out for quantitative evaluation of the CNT angular distribution. Young’s modulie and tensile strengths were evaluated using monotonic tensile testing at room temperature after molding prepreg into composites and resultant values were compared with theoretical estimations (Eshelby/Mori–Tanaka theory). Numbers of CNT in the composites orientation exceed 30 degree were relatively low, which were significantly improved with a small stretching ratio, however the misorientation at higher angle still remain, which means that stretching prepregs are effective for CNTs with small angle. Resultant Young's modulie of composites increased with stretching the prepreg. Young’s modulie estimated results by Eshelby/Mori–Tanaka theory were in good agreement with experimental ones, for small stretching ratio, however disagreed for over 10% stretching ratio.抄録全体を表示PDF形式でダウンロード (3005K) -
松尾 剛, 影山 和郎2014 年 40 巻 5 号 p. 218-226
発行日: 2014年
公開日: 2015/10/22
ジャーナル フリーA new compressive test method using a specimen with a shape of hourglass for unidirectional carbon fiber reinforced thermoplastic composites was proposed and confirmed to be capable of evaluating its compressive strength in fiber direction and failure mode with high reliability. In addition, it was theoretically verified that the elastic-plastic shear property in out-of-plane laminated direction has a great deal of influence on the compressive strength by a proposed modified Budiansky's solution considering some defined elastic and plastic parameters obtained from the shear experimental result as well as kink band angle and initial fiber misalignment. From this point of view, a strong correlation between the out-of-plane shear property of unidirectional fiber composite and the mechanical property of its matrix resin suggests that the viscoelastic plasticity of the matrix resin determines the temperature-dependent compressive strength in fiber direction. In this study, a novel method is applied to compressive test at various temperatures, and temperature-dependent compressive failure mode is investigated. It is indicated that the proposed modified Budiansky's solution has a certain availability to establish the relationship between the compressive strength and the out-of-plane shear property of unidirectional thermoplastic composites at any different temperature.抄録全体を表示PDF形式でダウンロード (2651K) -
松谷 浩明, 武田 一朗, 橋本 雅弘, 平野 啓之, 岡部 朋永2014 年 40 巻 5 号 p. 227-237
発行日: 2014年
公開日: 2015/10/22
ジャーナル フリーFlow of stampable thermoplastic sheet developed by Toray was simulated with moving particle semi-implicit method. The method was improved by introducing implicit method into velocity calculation, simplifying pressure calculation, applying parallel computing and parameterizing walls. These improvements made the present method about 80 times faster than basic MPS method. And the quaternion was introduced to calculate rotation of fiber assumed to be rigid in three dimensions. Then, compression molding of circular plate and rib was simulated with this improved MPS method. In circular plate case, computational result showed a similar tendency to experiment that the random orientation of fibers was kept through compression. And in rib case, computational results also showed a similar tendency to experiments that sheet was driven into rib keeping ply order, and that resin rich was formed depending on fiber length. The traditional computational methods such as finite element method and finite difference method are not good at these analyses of fiber orientation and resin rich (heterogeneity), and it is confirmed that the particle method is useful for these analyses.抄録全体を表示PDF形式でダウンロード (4176K)
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