Determination of Fracture Toughness for Wood
Publication: Journal of Structural Engineering
Volume 118, Issue 7
Abstract
Determination of fracture toughness values in modes I and II for wood are considered. The testing methods are based on the American Society for Testing and Materials standard “plane strain fracture toughness of metallic materials,” which considers mode I only. For the test, a modification of the standard is proposed. It is proposed that crack initiation be done with a very thin blade saw, and a larger nonlinearity of the load‐displacement curve is suggested. For the test, a similar testing and analysis method is applied to a beam specimen with an end crack. Fracture toughness values are presented, and their dependence on the material and experimental parameters is studied. For mode I., the orientation of the specimen is of great importance. For mode II, the most important variable is the density of the wood material. The fracture toughness value for modes I and II was not affected by the moisture content of the specimens in the range of 10‐20%.
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References
1.
“Standard test method for plane‐strain fracture toughness of metallic materials.” (1981). ASTM E399‐81, American Society for Testing and Materials, Philadelphia, Pa.
2.
“Standard test for 7IC, a measure of fracture toughness.” (1981). ASTM E813‐81, American Society for Testing and Materials, Philadelphia, Pa.
3.
Barrett, J. D., and Foschi, R. O. (1977). “Mode II stress‐intensity factors for cracked wood beams.” Engrg. Fract. Mech., 9(2), 371–378.
4.
Chisholm, D. B., and Jones, D. L. (1977). “An analytical and experimental stress analysis of a practical Mode II fracture test specimen.” Exp. Mech., 17(1), 7–13.
5.
Cramer, S. M., and Pugel, A. D. (1987). “Compact shear specimen for wood Mode II fracture investigations.” Int. J. Fract., 35(3), 163–174.
6.
Fonselius, M. (1986). “Fracture mechanics of spruce and PLV.” Report 80, Helsinki Univ. of Technology, Dept. of Civil Engineering, Espoo, Finland (in Swedish).
7.
Fonselius, M. (1991). “Long‐term fracture toughness of wood.” Res. Reports 718, Technical Research Centre of Finland, Espoo, Finland.
8.
Fonselius, M., and Riipola, K. (1989). “Determination of Mode II fracture toughness for wood.” Res. Reports 597, Technical Research Centre of Finland, Espoo, Finland (in Swedish).
9.
Hunt, D. G., and Croager, W. P. (1982). “Mode II fracture toughness of wood measured by a mixed mode test method.” J. Mater. Sci. Lett., 1(2), 77–79.
10.
Leicester, R. H. (1971). “Some aspects of stress fields at sharp notches in orthotropic materials. I. Plane stress.” CSIRO Australia Div. Forest Prod. Technol. Paper No. 57, Commonwealth Scientific and Industrial Research Organization, Melbourne, Australia.
11.
Mall, S., Murphy, J. F., and Schottafer, J. E. (1983). “Criterion for the mixed mode fracture in wood.” J. Engrg. Mech. Div., ASCE, 109(3), 680–690.
12.
Murphy, J. F. (1979). “Strength of wood beams with end splits.” Res. Paper FPL347, United States Forest Products Laboratory, Madison, Wis.
13.
Murphy, J. F. (1986). “Strength and stiffness reduction of large notched beams.” J. Struct. Engrg., ASCE, 112(9), 1989–2000.
14.
Murphy, J. F. (1988). “Mode II wood test specimen: Beam with central slit.” J. Test. Eval., 16(4), 364–368.
15.
Porter, A. W. (1964). “On the mechanics of fracture in wood.” Forest Prod. J., XIV(8), 325–331.
16.
Riipola, K. (1991). “Dimensioning of beams with cracks, notches and holes. An application of fracture mechanics.” Proc. CIB‐W18A Conf., Lisbon, Portugal.
17.
Riipola, K., and Fonselius, M. (1992). “Determination of critical J‐integral for wood.” J. Struct. Engrg., ASCE, 118(7), 1741–1750.
18.
Rolfe, S. T., and Barsom, J. M. (1977). Fracture and fatigue control in structures. Application of fracture mechanics. Prentice‐Hall, Inc., Englewood Cliffs, N.J.
19.
Smith, F. W., and Penney, D. T. (1980). “Fracture mechanics analysis of butt joints in laminated wood beams.” Wood Sci., 12(4), 227–235.
20.
Wright, K. (1986). “Fracture toughness of pine and spruce determined with the CT‐specimens.” Res. Reports 387, Technical Research Centre of Finland, Espoo, Finland (in Finnish).
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Copyright © 1992 ASCE.
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Published online: Jul 1, 1992
Published in print: Jul 1992
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