巻号一覧
37 巻 (2011)
- 6 号 p. 203-
- 5 号 p. 164-
- 4 号 p. 121-
- 3 号 p. 93-
- 2 号 p. 46-
- 1 号 p. 3-
37 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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河井 昌道, 木暮 尊志, 鈴木 崇史2011 年 37 巻 2 号 p. 46-57
発行日: 2011年
公開日: 2011/09/15
ジャーナル フリーOff-axis ratcheting behavior of a unidirectional carbon/epoxy (CFRP) laminate at high temperature has been examined with a particular emphasis on its load-waveform and fiber-orientation dependence. Development of an engineering model for describing the off-axis ratcheting deformation in unidirectional composites has also been attempted. First, off-axis ratcheting tests are performed on coupon specimens with different fiber orientations under different asymmetric cyclic loading conditions. Off-axis creep tests at constant loads equal in magnitude to the maximum levels of the ratcheting tests are also carried out, and the creep test results are compared with the ratcheting test results. Experimental results show that the off-axis ratcheting strain accumulates more as the stress ratio, i.e. the mean stress level, of cyclic loading becomes larger, regardless of fiber orientation. It is also found that the off-axis ratcheting is transient over the range of testing and similar to the off-axis creep in the unidirectional CFRP laminate in its stress, time and fiber-orientation dependence. Then, a simplified ratcheting model for transversely isotropic media is formulated by means of the classical Bailey-Norton equation and a newly defined effective stress that can account for the effect of the maximum stress as well as the mean stress of cyclic loading. It is shown that the proposed engineering ratcheting model allows predicting the off-axis ratcheting behavior of the unidirectional CFRP laminate for different fiber orientations over a range of stress ratio.抄録全体を表示PDF形式でダウンロード (1905K) -
横関 智弘2011 年 37 巻 2 号 p. 58-62
発行日: 2011年
公開日: 2011/09/15
ジャーナル フリーViscosity of CNT-dispersed polymer is predicted based on elasticity-based analogy. Micromechanical Mori-Tanaka approach is applied for the prediction of viscosity, and it is concluded that the elasticity-based model fits well with the experimental data. In addition, a semi-empirical model for non-Newtonian viscosity of CNT-dispersed polymer is proposed, and the predictions are verified with experimental results.抄録全体を表示PDF形式でダウンロード (873K) -
草野 英昭, 青木 雄一郎, 平野 義鎭, 永尾 陽典2011 年 37 巻 2 号 p. 63-69
発行日: 2011年
公開日: 2011/09/15
ジャーナル フリーThe objective of this study is to clarify the fracture behaviour of unidirectional CFRP (carbon fiber reinforced plastics) under static tensile loading. The advantages of CFRP are higher specific stiffness and strength than the metals. The use of CFRP is increasing in not only the aerospace and rapid transit railway industries but also the sports, leisure and automotive industries. There are some proposed theories to find out the tensile fracture of CFRP by using numerical calculation. But the tensile fracture mechanism of unidirectional CFRP has not been experimentally made clear because the fracture speed of unidirectional CFRP is quite high. We selected the intermediate modulus and high strength unidirectional CFRP laminate which is a typical material used in the aerospace field. The fracture process under static tensile loading was captured by high-speed camera and a new type high-speed video camera HPV-1. We succeeded in high-speed imaging of this fracture by HPV-1 at 125,000 frames per second. We clarified a high-speed fracture process by tensile test of CFRP.抄録全体を表示PDF形式でダウンロード (2965K)
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