巻号一覧
38 巻, 1 号
選択された号の論文の4件中1～4を表示しています
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研究論文
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高田 啓太, 小林 訓史, 宋 東烈2012 年 38 巻 1 号 p. 8-14
発行日: 2012年
公開日: 2012/12/10
ジャーナル フリーNatural fiber reinforced composite materials attracts much attention from a view point of a present global environmental problem. Continuous natural fiber reinforced thermoplastic composites have superior mechanical property and have often been expected for structural materials. However, it is difficult to impregnate reinforcement fibers with thermoplastics because of high viscosity of molten plastics. In this study, continuous natural fiber reinforced thermoplastic composites were molded using intermediate materials fabricated through the micro-braiding technique. Bamboo-rayon fiber and poly(lactic acid) (PLA) fibers were used as reinforcement and matrix, respectively. Composite plates were fabricated by hot press molding under various molding conditions, including molding temperature, pressure and time. Tensile and shear tests were conducted to evaluate the effect of molding condition on mechanical properties of the composites. Tensile and shear strength increased with increasing molding temperature, whereas they are little affected by molding pressure and time. It was clarified that molding temperature of 190°C, molding pressure of 1 MPa and molding time of 4 min is optimum molding condition considering tensile strength achievement ratio.抄録全体を表示PDF形式でダウンロード (2210K) -
上田 政人, 石井 雅人, 西村 哲2012 年 38 巻 1 号 p. 15-21
発行日: 2012年
公開日: 2012/12/10
ジャーナル フリーCompressive strength of unidirectional CFRP was estimated based on a model of column buckling on elastic foundation. It was shown that the compressive strength based on the column buckling model coincided with the compressive strength based on the fiber kinking model for high fiber volume fraction of the unidirectional CFRP. Apparent shear modulus of a carbon fiber in the in-phase buckling was calculated by the shear and bending deformation of the composite. The apparent shear modulus was decreased depending on the ratio of kink band length to the fiber diameter. Compressive strengths of unidirectional CFRPs were estimated by considering the apparent shear modulus. The estimated results for various types of unidirectional CFRP showed good agreement with the experimental results. Upper and lower limit of the compressive strengths of the unidirectional CFRPs were found out theoretically.抄録全体を表示PDF形式でダウンロード (781K) -
灘部 岳晃, 西川 雅章, 水口 周, 中村 達也, Siivola Juho T., 武田 展雄2012 年 38 巻 1 号 p. 22-29
発行日: 2012年
公開日: 2012/12/10
ジャーナル フリーThe health monitoring technique of composite bolted joints is currently being developed by means of the strain distribution measurement using optical fiber sensor. This study proposed a finite element model to simulate the strain distribution after the damage initiation in bearing failure of CFRP bolted joints, and investigated the relationship between the damage state and the strain distribution. The finite element model was constructed by extending our previous model of the bearing failure in CFRP bolted joints. In this model, the damage in 0° and ±45° plies in the laminate is addressed by the progressive damage model and the plastic deformation is simulated in 90° plies. The simulated results of the plastic strain in fiber direction in 90° ply during the damage evolution revealed a strong correlation between the plastic strain distribution and the damage area of the fiber kinking in 0° ply. These results confirmed the measurement results by Minakuchi et al., demonstrating that the kinking damage area in 0° ply could be evaluated by measuring the residual strain distribution.抄録全体を表示PDF形式でダウンロード (1861K) -
竹内 博紀, 斎藤 博嗣, 金原 勲2012 年 38 巻 1 号 p. 30-37
発行日: 2012年
公開日: 2012/12/10
ジャーナル フリーIn this study, the crack suppression mechanism in the thin-ply laminate was discussed by the mesoscopic finite element analysis. The intraply crack extension in the thin ply 90° layer, which has the thickness from 40 to 150 μm, was simulated with the cohesive element. In addition, the effect of initial defect on the crack extension behavior was also discussed. The crack extension behavior showed good agreement with the experimental results in any ply thickness for 6 J/m2 was applied to the cohesive energy. The crack initiation strain was not influenced by the existence of the initial defect up to 10 μm length. However the crack initiation strain was not influenced by the ply thickness, the crack penetration strain tended to increase with decrease of ply thickness.抄録全体を表示PDF形式でダウンロード (4842K)
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