巻号一覧
35 巻 (2009)
- 6 号 p. 233-
- 5 号 p. 185-
- 4 号 p. 141-
- 3 号 p. 99-
- 2 号 p. 49-
- 1 号 p. 3-
35 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
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研究論文
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加藤木 秀章, 竹村 兼一2009 年 35 巻 6 号 p. 233-240
発行日: 2009年
公開日: 2010/12/25
ジャーナル フリーIn this study, effects of water absorption on flexural strength and creep property of carbon fiber reinforced composite (CFRP) as well as epoxy resin were examined. Weight gains were measured after immersion in distilled water at room temperature, 50°C, 70°C and 90°C. Static flexural tests were conducted after immersion for 30 and 60 days. The flexural creep test of CFRP was carried out in the temperature range from 50°C to 80°C. As a result, weight gain increased with an increase of water temperature for the both CFRP and epoxy. Weight gain after 30 days at 90°C was not saturated, that was caused by the crack initiation in the matrix. The flexural strength of CFRP was decreased with an increase of water temperature of immersion, because of increasing number of cracks in matrix and debondings at the interface between fiber and matrix. The dimension of thickness also increased. The time to creep fracture was dependent on the temperature of environmental water. The steady state creep rate was much increased for CFRP immersed in a water over 70°C.抄録全体を表示PDF形式でダウンロード (2502K) -
荒尾 与史彦, 小柳 潤, 宇都宮 真, 寺田 裕, 川田 宏之2009 年 35 巻 6 号 p. 241-247
発行日: 2009年
公開日: 2010/12/25
ジャーナル フリーIn this study, we focused on the geometrical change of cross-ply laminates that are widely used for the composite structures. The behavior of time-dependent out-of-plane deformation under high temperature and humidity was examined. The CFRP plates were exposed at 80°C, 90% RH and their change in geometry was measured at arbitrary elapsed time. The initial shape of the specimens was twisted saddle shape, and the shape gradually became flat with time. Up to 500 μm of out-of-plane deformation arose during moisture absorption for CFRP symmetric plate with the size of 280×280×2.4 mm. The displacement in the thickness direction was the most along ±45° directions in which reinforcing fiber was not aligned. Finite element analysis (FEA) was performed to simulate the out-of-plane deformation of cross-ply laminates. The diffusivities D and coefficient of moisture expansion β, which were obtained other experiments in authors' previous work (Arao et al.: Adv. Compos. Mater., 17 (2008), 359-372), were used. The ply angle misalignment was considered as factors of generating out-of-plane deformation. For the analytical results, it was confirmed that the model the surface layer of which was rotated 1° deformed approximately 700 μm, and the plate geometry became twisted saddle shape by moisture absorption.抄録全体を表示PDF形式でダウンロード (839K) -
原 栄一, 横関 智弘, 八田 博志, 石川 隆司2009 年 35 巻 6 号 p. 248-255
発行日: 2009年
公開日: 2010/12/25
ジャーナル フリーReliable out-of-plane tensile test methods for adequate measurement of out-of-plane mechanical properties (e.g. strength) of laminated composites remain to be established. The present study focuses on the flatwise tension test using cylindrical column and spool column specimens for the measurement of out-of-plane tensile strength. Finite element analyses and experiments of unidirectional CFRP laminates were carried out in order to investigate the effect of specimen configuration on the out-of-plane tensile strength. A suitable guideline for evaluation of the out-of-plane strength was suggested based on the experimental and analytical results.抄録全体を表示PDF形式でダウンロード (1450K) -
岡部 朋永, 茂谷 尊, 西川 雅章, 橋本 雅弘2009 年 35 巻 6 号 p. 256-265
発行日: 2009年
公開日: 2010/12/25
ジャーナル フリーDiscontinuous fiber reinforced plastics have superior productivity and formability in comparison with continuous fiber reinforced plastics. However, their strengths are remarkably low. Thus there is an urgent need to establish a fundamental model in order to improve the strength of discontinuous fiber reinforced plastics. In the present work, we utilized numerical simulations that consider the microscopic damage in the composite and incorporate an individual constitutive law of thermosetting resin or thermoplastic resin. The fundamental mechanism that affected the strength and failure of the composite was investigated when the fiber length and/or matrix properties were varied from continuous glass fiber reinforced plastics to discontinuous glass fiber reinforced plastics. Our results clarified two factors that cause the strength degradation of discontinuous fiber reinforced plastics. One is the low yield stress of thermoplastic resin, which is frequently used for the matrix of discontinuous fiber reinforced plastics. As the other factor, the final failure mode is changed from fiber breaking mode to matrix cracking mode in the case of the low fiber volume fraction of discontinuous glass fiber reinforced plastics. Moreover, we investigated the relationship between fiber length and strength of carbon fiber reinforced polypropylene and the effect of thermoplastic matrix properties depending on the loading rate as well.抄録全体を表示PDF形式でダウンロード (2056K)
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