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Abstract: The paper discusses the results of experimental, numerical, and micro-structural investigations of mixed mode I/II fracture of pine wood (Pinus sylvestris L.) for the TL and RL crack propagations systems. The critical energy release rates, were used as a fracture toughness parameter. The acoustic emission method was applied to determine the crack initiation moment and the critical load. A mixed mode bending (MMB) apparatus and MMB specimens were used for the first time to determine the fracture toughness of pine wood under mixed mode I/II loading. The critical energy release rates, GI and GII, were established for different GI/GII ratios. They were used to assess fracture toughness of pine wood at different mode-I-to-mode-II-loading component ratios, and propose the fracture conditions for the mixed mode I/II loading. These conditions can be applied in a safety analysis of cracked structural pine wood elements subjected to mixed mode I/II loading. By applying a scanning photography technique, it was possible to examine the mechanisms of micro-fracture at the cell level of pine wood under mixed mode I/II loading.
B I B L I O G R A F I A1. D. ATACK, W. D. MAY, E. L. MORRIS, R. N. SPROULE, The energy of tensile and cleavage fracture of black spruce, Tappi, 44, 555-567, 1961.
2. A. W. PORTER, On the mechanics of fracture in wood, Forest Products Journal, 14, 325-331, 1964.
3. G. R. DEBAISE, A. W. PORTER, R. E. PENTONEY, Morphology and mechanics of wood fracture, Materials Research & Standards, 6, 493-499, 1966.
4. A. P. SCHNIEWIND, R. A. POZNIAK, On the fracture toughness of Douglas fir wood, Engineering Fracture Mechanics, 2, 223-233, 1971.
5. A. P. SCHNIEWIND, D. E. LYON, A fracture mechanics approach to the tensile strength perpendicular to grain of dimension lumber, Wood Science And Technology, 7, 45-59, 1973.
6. A. P. SCHNIEWIND, J. C. CENTENO, Fracture toughness and duration of load factor I. Six principal systems of crack propagation and the duration factor for cracks propagating parallel to grain, Wood andFiber, 5, 152-159, 1973.
7. A. P. SCHNIEWIND, Fracture toughness and duration of load factor II. Duration factor for cracks propagating perpendicular-to-grain, Wood and Fiber, 9, 216-226, 1977.
8. J. A. JOHNSON, Crack initiation in wood plates, Wood Science, 6, 151-158, 1973.
9. . PETTERSON, J. BODIG, Prediction of fracture toughness of conifers, Wood and Fiber Science, 15, 302-316, 1983.
10. B. YEH, A. P. SCHNIEWIND, Elasto-plastic fracture mechanics of wood using the J-integral method, Wood and Fiber Science, 24, 364-376, 1992.
11. K. ANDO, K. SATO, M. FUSHITANI, Fracture toughness and acoustic Emission characteristics of wood II. Effects of grain angle, Mokuzai Gakkaishi, 38, 342-349, 1992.
12. K. ANDO, M. OHTA, Relationships between the morphology of micro-fractures of wood and the acoustic emission characteristics, Mokuzai Gakkaishi, 41, 640-646, 1995.
13. S. E. STANZL-TSCHEGG, D. M. TAN, E. K. TSCHEGG, New splitting method for wood fracture characterization, Wood Science and Technology, 29, 31-50, 1995.
14. S. E. STANZL-TSCHEGG, D. M. TAN, E. K. TSCHEGG, Fracture resistance to the crack propagation in wood, International Journal of Fracture, 75, 347-356, 1996.
15. A. REITERER, S. E. STANZL-TSCHEGG, E. K. TSCHEGG, Mode I fracture and acoustic emission of softwood and hardwood, Wood Science and Technology, 34, 417-430, 2000.
16. G. PROKOPSKI, Badania odporności na pękanie drewna, Tests of wood fracture toughness, Archiwum Inżynierii Lądowej, 37, 279-288, 1991.
17. G. PROKOPSKI, Effect of moisture content on fracture toughness of wood, Archives of Civil Engineering, 43, 217-227, 1997.
18. G. PROKOPSKI, The application of fracture mechanics to the testing of wood, Journal of Materials Science, 28, 5995-5999, 2004.
19. G. R. DEBAISE, Mechanics and morphology of wood shear fracture, Ph. D. Thesis, State University College of Forestry, Syracuse University, Syracuse, New York, 1970.
20. J. D. BARRETT, R. O. FOSCHI, Mode II stress-intensity factors for cracked wood beams, Engineering Fracture Mechanics, 9, 371-378, 1977.
21. S. M. CRAMER, A. D. PUGEL, Compact shear specimen for wood mode II fracture investigations, International Journal of Fracture, 35, 163-174, 1987.
22. G. PROKOPSKI, Investigation of wood fracture toughness using mode II fracture (shearing), Journal of Materials Science, 30, 4745-4750, 1995.
23. S. Xu, H. W. REINHARDT, M. GAPPOEV, Mode II fracture testing metod for highly orthotropic materials like wood, International Journal of Fracture, 75, 185-214, 1996.
24. S. E. STANZL-TSCHEGG, D. M. TAN, E. K. TSCHEGG, Mode II fracture tests on spruce wood, Mokuzai Gakkaishi, 42, 642-650, 1996.
25. H. YOSHIHARA, M. OHTA, Measurement of mode II fracture toughness of wood by end-notched flexure test, Journal of Wood Science, 46, 273-278, 2000.
26. H. YOSHIHARA, Influence of span/depth ratio on the measurement of mode II fracture toughness of wood by end-notched flexure test, Journal of Wood Science, 47, 8-12, 2001.
27. E. M. Wu, Application of fracture mechanics to anisotropic plates, Journal of Applied Mechanics. 34, 967-974, 1967.
28. R. H. LEICESTER, Application of linear fracture mechanics in the design of timber structures, [In:] Proc. Conference Australian Fractured Group, 23, 156-164, Melbourne, 1974.
29. J. G. WILLIAMS, M. W. BIRCH, Mixed mode fracture in anisotropic media, cracks and fracture, [In:] ASTM STP Cracks And Fracture, 601, 125-137, 1976.
30. S. MALL, J. F. MURPHY, M. ASCE, J. E. SHOTTAFER, Criterion for mixed mode fracture in wood, Journal of Engineering Mechanics, 109, 680-690, 1983.
31. E. K. TSCHEGG, A. REITERER, T. PLESCHBERGER, S. E. STANZL-TSCHEGG, Mixed mode fracture energy of sprucewood, Journal of Materials Science, 36, 3531-3537, 2001.
32. P. G. KOSSAKOWSKI, An analysis of mixed mode fracture toughness of pine wood beam elements, PhD. Thesis, Faculty of Civil and Environmental Engineering, Kielce University of Technology, Kielce 2004.
33. C. W. Woo, C. L. CHOW, Mixed mode fracture in orthotropic media, Fracture Mechanics in Engineering Application, Sih G. C., Valluri S. R., [Eds.], Sijthoff and Noordhoff, Rockville, 387-396, 1979.
34. P. G. KOSSAKOWSKI, Fracture toughness of pine wood for I and II loading modes, Archives of Civil Engineering, 54, 510-530, 2008.
35. PN-EN 380:1998 Timber structures - Test methods - General principles for static load testing.
36. PN-EN 384:1999 Structural timber - Determination of characteristic values o f m chanical properties and density.
37. PN-EN 408:1998 Timber structures - Structural timber and glued laminated timber - Determination of some physical and mechanical properties.
38. J. BODIG, J. R. GOODMAN, Prediction of elastic parameters for wood, Wood Science 5, 249-264, 1973.
39. C. LEWINOWSKI, Matematyczna analiza wyników badań przeprowadzanych w laboratoriach drogowych, Prace COBiRTD, Warszawa 1968.
40. F. DUCEPT, P. DAVIES, D. GAMBY, An experimental study to validate tests used to determine mixed mode failure criteria of glass/epoxy composites, Composites Part A, 28a, 719-729, 1997.
41. J. R. REEDER, J. R. CREWS Jr, Mixed-mode bending metod for delamination testing, AIAA Journal, 28, 1270-1276, 1990.
42. A. J. KINLOCH, Y. WANG, J. G. WILLIAMS, P. YAYLA, The Mixed-mode delamination of fibre composite materials, Composite Science and Technology 47, 225-237, 1993.
43. M. KENANE, M. L. BENZEGGAGH, Mixed-mode delamination fracture toughness of unidirectional glass/ epoxy composites under fatigue loading, Composite Science Technology, 57, 597-605, 1997.
44. K. N. SHIYAKUMAR, J. H. CREWS Jr, V. S. AVVA, Modified mixed-mode bending test apparatus for measuring delamination fracture toughness of laminated composites, Journal of Composite Materials, 32, 804-828, 1998.
45. N. SVENSSON, R. SHISHOO, M. GILCHRIST, Interlaminar fracture commingled GF/PET composite laminates, Journal of Composite Materials, 32, 1808-1835, 1998.
46. ADINA, Theory and Modelling Guide. Volume 1: ADINA, ADINA System Online Manuals, Report ARD 06-7, 2006.
47. S. MINDESS, A. BENTUR, Crack propagation in notched wood specimens with different grain orientations, Wood Science and Technology, 20, 145-155, 1986.
48. W. A. CÔTÉ, R. B. HANNA, Ultrastructural characteristics of wood fracture surfaces, Wood and Fiber Science, 15, 135-163, 1983.