著者

藤田 和宏 永井 英幹 岩下 哲雄

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.71, no.5, pp.461-466, 2022-05-15 (Released:2022-05-20)

参考文献数

19

被引用文献数

1

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Carbon fiber is a brittle material and its tensile strength is strongly influenced by defects, which are often assessed by the shape parameter of the Weibull distribution. Therefore, the shorter the gauge length is, the higher the tensile strength is. The usual tensile test is conducted with a gauge length of 25 mm and the tensile strength at short gauge is derived using Weibull distribution. However, it is reported that the shape parameter changes when the gauge length is less than 1mm. The objective of this work is to attempt to evaluate the short gauge tensile strength of carbon fiber in tests under optical microscope observation. The shorter the gauge length was, the more test results of fiber separation from adhesive or fiber breakage in adhesive were observed. It is found that the test of short gauge of 0.2 mm requires careful specimen preparation to avoid shear stress due to misalignment of fiber and loading axes. Weibull shape parameters of the tensile strengths at the gauges from 50mm to 1mm were almost the same as the usual tensile test. However, the values for the 0.5 mm and 0.2 mm gauges were higher than those for the longer gauges.

著者

岩下 哲雄

出版者

THE CARBON SOCIETY OF JAPAN

雑誌

炭素 (ISSN:03715345)

巻号頁・発行日

vol.2003, no.207, pp.78-86, 2003-05-15 (Released:2010-06-28)

参考文献数

14

被引用文献数

3 3

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X-ray dill faction technique, have widely been ftpplicd for crystal structure charactcniation of carbon materi-als and ga c useful information. Progresses, in computer. were remarkable. which made the measurement cI diffrac-tion intensities and their correction, on di fferent factors easier. It was pointed out, therefore, that the procedures for X-ray diffraction measurements, e to he revised so as to take into account of these progresses in computation. In the present paper, computer analysts of digital data of X-ray diffraction, for instance, determination of lattice constants and crystallite size of carbon materials (Gakushin method) using profile fitting technique and calculation of integral inten-sity in the case of estimation of graphititation degree P1 was reviewed. The measurement conditions to obtain a good digital diffraction data, the procedures of smoothing and intensity correction of diffraction profile were introduced.