Experimental Study of Furfurylation Effect on Fracture of Beech Wood under Mixed Mode

Document Type : Research Paper

Authors

1 Graduated Ph.D., Department of Wood and Paper Science & Technology, Faculty Natural of Resources, University of Tehran, Karaj, I.R. Iran

2 Assistant Professor, Department of Wood and Paper Science & Technology, Faculty Natural of Resources, University of Tehran, Karaj, I.R. Iran

3 Professor, Department of Wood and Paper Science & Technology, Faculty Natural of Resources, University of Tehran, Karaj, I.R. Iran

Abstract

Fracture of mixed mode I/II in beech wood and its wood polymers has been investigated experimentally in this study. Hence, two crack systems of TL and RL were selected in which the crack planes extend along the wood fibers. This investigation has demonstrated that onset of mixed mode cracking can be predicted with a very simple fracture criterion in these crack systems. Results indicated that fracture critical loading is affected by furfurylation and also load-displacement curves of specimens were changed. Variations in fracture toughness values of mixed mode I/II can be occurred following variations of fracture critical forces. In the both crack systems, KIC/KIIC distribution trend is changed by furfurylation that indicates changing of material nature by furfurylation. Results of scanning electron microscopy (SEM) analyses indicated that micro cracks occurrence in wood polymer structure may be one of the factors caused to change in fracture toughness; these changes occur simultaneously with material nature modification followed by increasing of shear strength parallel to the grain due to polymerization.

Keywords


[1].  Goldstein, I. S. and Dreher, W. A. (1960). Stable furfuryl alcohol impregnating solution. Industrial and Engineering Chemistry Research, 52(1): 57–58.
[2].  Anderson, T. L. (2005). Fracture mechanics, fundamentals and applications, CRC Press: Taylor and FrancesGroup, Boca Raton, FL.
[3].  AFPA, (2007). National design specificationfor wood construction, American Forest and Paper, Association, Washington, DC.
[4].  Smith, I., Landis, E., and Gong, M. (2003). Fracture and Fatigue in Wood, Wiley.
[5].  Bodig, J. and Jayne, B. A. (1982). Mechanics of Wood and Wood Composites, Translated by Ebrahimi, Gh., University of Tehran Press, Tehran.
[6].  Rathkjen, A. (1993). Fracture Criteria for Wood, J.P. Boehler (ed), Rotterdam.
[7].  Mall, S., Murphy, J. F., and Shottafer, J. E. (1983). Criterion for mixed mode fracture in wood. Journal of Engineering Mechanics,109: 680–90.
[8].  Broek, d. (1982). Elementary Engineering Fracture Mechanics, martinus nijhoff, London.
[9].  Valentin, G. and Caumes, P. (1989). Crack propagation in mixed mode in wood: a new specimen. Wood Science and Technology, 23: 43–53.
[10].   Jernkvist, L. O. (2001). Fracture of wood under mixed mode loading II. Experimental investigation ofPicea abies. Engineering Fracture Mechanics, 68: 565-576.
[11].   Abdolzadeh, H., Ebrahimi, Gh., Layeghi, M., Ghassemieh, M., and Mirshokraei, S.A. (2013). Mechanical properties of Beech-Furfuryl alcohol wood polymer. Iranian Journal of Wood and Paper Industries, 4(2):143-156.
[12].   de-Moura, M. F. S. F., Morais, J. J. L., and Dourado, N. (2008). A new data reduction scheme for mode I wood fracture characterization using the double cantilever beam test. Engineering Fracture Mechanics, 75: 3852–3865.
[13].   Thuvander, F. and Berglund, L. A. (2000). In situ observations of fracturemechanisms for radial cracks in wood. Journal of Material Science, 35:6277–6283.
[14].   Watanabe, K., Shida, S., and Ohta, M. (2011). Evaluation of end-check propagation based on mode I fracture toughness of sugi (Cryptomeria japonica). Journal of Wood Science, 57:371–376.
[15].   Buchelt, B., Dietrich, T., and Wagenfuhr, A. (2012). Macroscopic and microscopic monitoring of swelling of beech wood after impregnation with furfuryl alcohol. European Journal of Wood and Wood Products, 70(6): 865-869.