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形態: 図版あり, Physical characteristics: Original contains illustrations, 資料番号: PA2120068000

形態: 図版あり, Physical characteristics: Original contains illustrations, 資料番号: PA2110071000

形態: 図版あり, Physical characteristics: Original contains illustrations, 資料番号: PA1710056000

形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA0062291015, レポート番号: JAXA-SP-13-014

第21回宇宙構造・材料シンポジウム（2005年12月5日. 宇宙航空研究開発機構宇宙科学研究本部 (JAXA)(ISAS)）, 相模原市, 神奈川県, 21st Symposium on Aerospace Structure and Materials (December 5, 2005. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 資料番号: SA6000020007

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 rations 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., 形態: 図版あり, Physical characteristics: Original contains illustrations, 資料番号: PA1520016000

繊維強化複合材料を実際に構造部材料として用いる場合,静的な荷重ばかりでなく動的な荷重を受けることが少なくない.特に,繊維強化方向に垂直方向の衝撃力に対する応答が最も重要であるが,未だこの分野の研究は少ない.そこで,本報告ではまず,応力波伝播の一次元理論を用いて,異種材料から成る材料の境界面での反射,伝達を扱った.次にそれを基礎として,様々な一方向繊維強化複合材料の簡単なモデルについてその繊維垂直方向の衝撃応答を計算した.モデルI,IIは無限体中に薄い帯状部分が存在する場合であり,モデルIII,IVはそれぞれ2層または3層から成る材料の場合である.以上のモデルについて,衝撃荷重下では静的荷重下より境界面において大きな引張応力が生じ,境界面での引張破壊が生じやすいことがわかった., Fiber-reinforced composite materials receive not only a static force but a dynamic force when they are used in practical structures. Especially, the impact response in the direction perpendicular to fibers is the most important, but tardy in research. In this report, first we treat wave reflection and transmission at the interface of different element materials, by using the one-dimensional theory of stress waves. Secondly, those results are applied to some simple models of unidirectional fiber-reinforced composite materials and impact responses in the direction perpendicular to fibers are calculated. Model I and II are composite structures in which two semi-infinite elastic solids are bonded with a thin layer made of a different material. Model III and IV are composed of two and three bonded layers, respectively. These models subjected to impact loading receive a larger tensile stress at the interface than those subjected to static loading, and it is predicted that the tensile fracture at the interface easily occurs., 資料番号: SA0125656000