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Journal of Wood Science

Official Journal of the Japan Wood Research Society

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Measurement of mode II fracture toughness of wood by the end-notched flexure test

Journal of Wood Science volume 46, pages 273–278 (2000)Cite this article

Abstract

We examined the applicability of end-notched flexure (ENF) tests for measuring the mode II fracture toughness of wood. Western hemlock (Tsuga heterophylla Sarg.) was used for the specimens. The fracture toughness at the beginning of crack propagationG IIc and that during crack propagationG IIR were calculated from the loadloading point compliance and load-crack shear displacement (CSD) relations. The obtained results were compared with each other, and the validity of measurement methods were examined. The results are summarized as follows: (1) The value ofG IIc increased with the increase in initial crack length. When measuringG IIc by ENF tests, we should be aware of the dependence ofG IIc on the initial crack length. (2) The value ofG IIR initially increased with the crack length, and it reached a constant value. (3) Measurement of the CSD is recommended when obtainingG IIR because the crack length, which has a great influence on theG IIR calculation, is implicitly included in the CSD. (4) We found that the crack length during its propagation should be evaluated by the final crack length.

References

  1. Barrett JD, Foschi RO (1977) Mode II stress-intensity factors for cracked wood beams. Eng Fract Mech 9:371–378

    Article  Google Scholar 

  2. Cramer SM, Purge AD (1987) Compact shear specimen for wood mode II fracture investigations. Int J Fract 35:163–174

    Article  Google Scholar 

  3. Murphy JF (1988) Mode II wood test specimen: beam with center slit. J Test Eval 16:364–368

    Article  Google Scholar 

  4. Prokopski G (1995) Investigation of wood fracture toughness using mode II fracture (shearing). J Mater Sci 30:4745–4750

    Article  CAS  Google Scholar 

  5. Stanzl-Tschegg SE, Tan DM, Tschegg EK (1996) Mode II fracture tests on spruce wood. Mokuzai Gakkaishi 42:642–650

    Google Scholar 

  6. Xu S, Reinhardt HW, Gappoev M (1996) Mode II fracture testing method for highly orthotropic materials like wood. Int J Fract 75:185–214

    Article  Google Scholar 

  7. Aicher S, Boström L, Gierl M, Kretschmann D, Valentin G (1997) Determination of fracture energy of wood in mode II. RILEM TC 133 report

  8. Russell AJ, Street KN (1985) Moisture and temperature effects on the mixed-mode delamination fracture of unidirectional graphite/ epoxy. ASTM STP 876:349–370

    CAS  Google Scholar 

  9. Gillespie JW Jr, Carlsson LA, Pipes RB (1986) Finite element analysis of the end notched flexure specimen for measuring mode II fracture toughness. Comp Sci Technol 27:177–197

    Article  CAS  Google Scholar 

  10. Kageyama K, Kikuchi M, Yanagisawa N (1991) Stabilized end notched flexure test: characterization of mode II interlaminar crack growth. ASTM STP 1110:210–225

    Google Scholar 

  11. Tanaka K, Kageyama K, Hojo M (1995) Prestandardization study on mode II interlaminar fracture toughness test for CFRP in Japan. Composites 26:257–267

    Article  CAS  Google Scholar 

  12. Williams JG (1989) The fracture mechanics of delamination tests. J Strain Anal 24:207–214

    Article  Google Scholar 

  13. Li Z-W, Kimpara I, Kageyama K, Suzuki T, Ohsawa I (1997) Testing method for evaluation of mode II fatigue delamination growth behaviors of advanced composite materials by applying CSD measurement (in Japanese). Trans Jpn Comp Mater 23:92–99

    Article  CAS  Google Scholar 

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Authors and Affiliations

  1. Faculty of Science and Engineering, Shimane University, 1060 Nishikawazu-cho, Matsue, 690-8504, Shimane, Japan

    Hiroshi Yoshihara

  2. Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, 113-8657, Tokyo, Japan

    Masamitsu Ohta

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  1. Hiroshi Yoshihara
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  2. Masamitsu Ohta
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Correspondence to Hiroshi Yoshihara.

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Yoshihara, H., Ohta, M. Measurement of mode II fracture toughness of wood by the end-notched flexure test. J Wood Sci 46, 273–278 (2000). https://doi.org/10.1007/BF00766216

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  • DOI: https://doi.org/10.1007/BF00766216

Keywords

  • Fracture Toughness
  • Crack Length
  • Energy Release Rate
  • Initial Crack Length
  • Western Hemlock