巻号一覧
30 巻 (2004)
- 6 号 p. 219-
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- 4 号 p. 135-
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30 巻, 4 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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規格化電位差法の適用とはく離形状の影響評価上田 政人, 轟 章, 島村 佳伸, 小林 英男2004 年 30 巻 4 号 p. 135-141
発行日: 2004/07/15
公開日: 2009/08/11
ジャーナル フリーMonitoring of delamination is indispensable for CFRP structures. In authors' previous studies, the delamination can be monitored with electric resistance change method. This method provided excellent performance of estimations. However, the method requires complicated electric circuits and uses a two-probe method: electrical resistance at electrodes has significant effect. To resolve these problems, an electrical voltage change method is adopted in the present study. Since the electrical voltage change method provides poor performance of estimations in our previous study, the present study employs a standardization method that has shown significant improvement of estimations for the electrical resistance change method. Moreover, the effect of zigzag shape of delaminations caused by the matrix cracking on the performance of estimations is investigated using FEM analyses. As a result, the electrical voltage change method shows good performance of estimations for delaminations located near the edges of the specimen and poor performance near the middle of the specimen. The zigzag shape has large effect on the performance of estimations when the delamination locates near the middle of the specimen. FEM analyses show the small electrical current through the thickness direction near the middle of the specimen causes these effects on the performance of estimations.抄録全体を表示PDF形式でダウンロード (7579K) -
笹山 秀樹, 川邊 和正, 友田 茂, 大澤 勇, 影山 和郎, 小形 信男2004 年 30 巻 4 号 p. 142-148
発行日: 2004/07/15
公開日: 2009/08/11
ジャーナル フリーCarbon fiber tows are generally used for the reinforcement of plastics. Recently, we have developed a method in which tow can be efficiently spread without causing any fiber damage (FUKUI method). By using this method, we prepared thin laminas about 0.05 mm in thickness, and produced quasi-isotropic laminates by stacking these laminas. Furthermore, we obtained the laminas having an arbitrary thickness by stacking the laminas with the same unidirectional prepregs. In this work, the effects of the lamina thickness on the first ply failure occurred in multidirectionally laminated composites have been studied. Tensile tests were performed on the samples and also acoustic emission was monitored during the tests. It is found that the initial failure stress increases with decreasing lamina thickness. This result can be predicted by Kageyama's study.抄録全体を表示PDF形式でダウンロード (7443K) -
同定誤差原因と2段階はく離同定による改善上田 政人, 轟 章, 島村 佳伸, 小林 英男2004 年 30 巻 4 号 p. 149-156
発行日: 2004/07/15
公開日: 2009/08/11
ジャーナル フリーMonitoring of delamination is indispensable for CFRP structures. In authors' previous studies, the delamination can be monitored with the electric resistance change method. This method provided excellent performance of estimations. However, the method requires complicated electric circuits and uses a two-probe method: electric resistance at the electrodes has significant effect. To resolve these problems, an electrical voltage change method is adopted in the present study. Since the electrical voltage change method provides poor performance of estimations in our previous study, the present study employs a standardization method that has shown significant improvement of estimations for the electrical resistance change method. As a result, the electrical voltage change method shows good performance of estimations for delaminations located near the edges of the specimen and poor performance near the middle of the specimen. The zigzag shape has large effect on the performance of estimations for the delamination near the middle of the specimen. In this paper, two-stage delamination monitoring method that is not affected by the shape of delamination is proposed. The validity of this method is verified using the FEM analysis.抄録全体を表示PDF形式でダウンロード (8391K) -
松崎 亮介, 轟 章, 小林 英男, 島村 佳伸2004 年 30 巻 4 号 p. 157-164
発行日: 2004/07/15
公開日: 2009/08/11
ジャーナル フリーStrain monitoring of automobile tires in-service is quite effective for improving the reliability of tires and ABS (Anti-lock Braking System). In a previous study, the authors proposed a new wireless strain monitoring method which is adopted in the tire itself as a sensor with an oscillator circuit. This method is simple and useful, but it requires a battery to activate the oscillator circuit. In the present study, a new passive wireless strain measurement system utilizing capacitance change of tires is proposed and experimentally investigated. The system consists of external antennas and strain sensor with an inductance-capacitance (LC) resonant circuit. The wireless system utilizes electromagnetic coupling between two inductors of the antenna and the sensor. This method enables us to use a part of an actual tire as a capacitor of the LC circuit. Deformation of the tire causes a resonant frequency change of the sensor. This resonant frequency change is measured as a change in the phase angle of the antenna by using electromagnetic induction. Tensile tests are performed and the phase angles are simultaneously measured. As a result, the method is experimentally shown to be effective as a passive wireless strain monitoring of tires.抄録全体を表示PDF形式でダウンロード (8222K)
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