Fracture toughness estimation of small diameter fibers

S. Ochiai, K. Morishita, S. Kuboshima, H. Okuda, T. Inoue, T. Ishikawa, M. Sato

研究成果: Chapter in Book/Report/Conference proceedingConference contribution

抄録

In estimation of fracture toughness of small diameter (5∼15 um) fibers, the difficulty arises from the small physical dimensions, due to which proper method to introduce small notches is limited. Also, the diameter is usually different among the fiber test specimens. Accordingly, a proper method to introduce an artificial notch in the specimens is required, and the fracture toughness value shall be estimated for each fiber test specimen. In the present work, as the method to introduce artificial notch, focused-ion (Ga +)-beam was used, with which a mode I type straight-fronted edge notch was introduced in the fiber specimens. The notch-tip radius was around 25 nm. The fracture strength (af), notch depth (a) and fiber diameter (D) were measured for each fiber test specimen. The correction factor Y for the present straight-fronted edge notch, which is a function of a relative notch depth a/D was calculated by the finite element method. The fracture toughness KIc was estimated for each fiber specimen by substituting the measured values of a, D and σf and calculated value of Y into KIc=Yσf (πa)1/2. Such an approach was applied to the polycrystalline SiC fiber (Tyranno-SA® with diameter 5∼11μm) and amorphous SiC fiber (Tyranno-ZMI® with diameter 9∼14 um). The fracture toughness values of the polycrystalline and amorphous SiC fibers were estimated to be 2.7±0.4 and 1.8±0.3 Mpa *m1/2, respectively. The fracture toughness value was almost independent of the fiber diameter and notch depth in both fibers.

本文言語英語
ホスト出版物のタイトル12th International Conference on Fracture 2009, ICF-12
ページ1548-1554
ページ数7
出版ステータス出版済み - 2009
外部発表はい
イベント12th International Conference on Fracture 2009, ICF-12 - Ottawa, ON, カナダ
継続期間: 7 12 20097 17 2009

出版物シリーズ

名前12th International Conference on Fracture 2009, ICF-12
2

その他

その他12th International Conference on Fracture 2009, ICF-12
Countryカナダ
CityOttawa, ON
Period7/12/097/17/09

All Science Journal Classification (ASJC) codes

  • Geotechnical Engineering and Engineering Geology

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