巻号一覧
40 巻 (2014)
- 6 号 p. 275-
- 5 号 p. 209-
- 4 号 p. 146-
- 3 号 p. 98-
- 2 号 p. 55-
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40 巻, 2 号
選択された号の論文の3件中1～3を表示しています
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研究論文
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呉 丹, 坂田 憲泰, 邉 吾一, 倉石 宗一郎, 宮内 貴史, 曽根原 健夫2014 年 40 巻 2 号 p. 55-61
発行日: 2014年
公開日: 2015/03/17
ジャーナル フリーCFRPs have been used for main material of large scale wind turbine blades. However, there are some fears of damage in the thickness direction of CFRP laminates caused by impact loads because of short of fibers. In this study, the artificial lightning impact tests were carried out to clarify the influence of lightning impact to the CFRP sandwich wind turbine blade, and their damages were measured with an ultrasonic detection apparatus. Furthermore,the impulse hammer tests, the bending tests and the FEM analyses for the CFRP sandwich wind turbine blades were conducted, and their results before and after the artificial lightning impulse test were compared. Finally, the structural safety of the CFRP sandwich wind turbine blade received the lightning impact under centrifugal force was evaluated by the FEM results.抄録全体を表示PDF形式でダウンロード (2825K) -
松崎 亮介, 瀬戸 大悟, 轟 章, 水谷 義弘2014 年 40 巻 2 号 p. 62-70
発行日: 2014/03/15
公開日: 2015/03/17
ジャーナル フリーWhen geometry-anisotropic fabrics, in which the thickness and width of fiber bundles differ in the warp direction and weft direction, respectively, are used for resin transfer molding (RTM), microscopic porous structures along a flow path may depend on the resin flow direction. This study investigated the influence of woven fabrics' geometric anisotropy on inter-bundle void formation due to air entrapment at the flow front during RTM. The void content–resin flow velocity relationship was measured in warp (narrow and thick bundle) and weft (wide and thin bundle) directional impregnation. In experiments, warp directional impregnation indicated higher critical resin flow velocity of void formation and void content under a given resin flow velocity than in weft directional impregnation. Void formation was also largely affected by capillary fingering, where warp directional impregnation indicated a higher critical flow velocity of fingering formation. This may be because the gap between the fiber bundle and the mold surface is smaller in the warp direction; thus, the capillary force is higher, and fingering is facilitated compared with weft directional impregnation. Additionally, this may lead to a higher critical velocity of void formation and higher void content at a given flow velocity in warp directional impregnation.抄録全体を表示PDF形式でダウンロード (2416K) -
津村 祐介, 新玉 重貴, 西川 雅章, 北條 正樹2014 年 40 巻 2 号 p. 71-80
発行日: 2014/03/15
公開日: 2015/03/17
ジャーナル フリーThis paper describes a new method for measuring microscopic strain distribution in carbon fiber reinforced plastics (CFRP). This method aims to evaluate the effect of heterogeneity, e.g. voids caused by different pressure conditions in curing process, on transverse crack initiation. Local Area Gray Level Thresholding (LAGT) method is a new feature-based matching method that uses gray level difference between fibers and matrix in scanning electron microscope (SEM) pictures. This paper also proposes improved LAGT method adjusting gray level in local evaluating area. LAGT method and improved LAGT method were compared to existing methods, such as Phase-Only Correlation (POC) and Zero-mean Normalized Cross Correlation (ZNCC). Among these 4 methods, improved LAGT is less influenced by the noise from optical system and its measurement accuracy is better even if gray level gradient changes locally in evaluating area. The microscopic strain distribution in 90º layers under transverse tensile loading were obtained by fiber location search based on image analysis using the improved LAGT method, and the measured strains corresponded well with the strains calculated by beam theory and laminate theory. Applying the above-mentioned method to the laminates including voids, it became possible to evaluate the effect of void on microscopic strain distribution experimentally.抄録全体を表示PDF形式でダウンロード (3836K)
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