Influence of density on Mode I fracture behavior of southern yellow pine (Pinus taeda L.) wood

Yıl 2022, , 135 - 140, 30.06.2022

Arif Caglar Konukcu

https://doi.org/10.18182/tjf.1054428

Öz

This study aimed to investigate the influence of density on the fracture behavior of southern yellow pine (Pinus taeda L.) wood in radial-longitudinal crack propagation direction under mode I loading. The density of the crack-tip location for each fracture test block was determined by using an X-ray density profile analyzer. Three fracture parameters were obtained from the load-deformation curve of each fracture test block, namely fracture toughness, initial slope, and specific fracture energy. In general, the results showed that the fracture parameters were strongly influenced by the density. Crack-tip locations with higher density were found to be more resistant to crack initiation. The initial slope of the load-deformation curve increased as the crack density in the wood increased. As a result of the regression analysis, it was observed that there were positive and strong correlations between density and each fracture parameter.

Anahtar Kelimeler

Fracture, Fracture toughness, Southern yellow pine, Specific fracture energy, Initial slope

Yoğunluğun güney sarıçam (Pinus taeda L.) ağacının Mod I kırılma davranışı üzerine etkisi

Öz

Bu çalışma, güney sarıçam (Pinus taeda L.) odununun mod I yüklemesi altında radyal-boyuna çatlak ilerleme yönünde kırılma davranışına yoğunluğun etkisini araştırmayı amaçlamıştır. Her bir kırılma testi bloğu için çatlak ucu konumunun yoğunluğu, X-ışını yoğunluk profili analizörü kullanılarak belirlenmiştir. Her bir kırılma test bloğunun yük-deformasyon eğrisinden başlangıç eğimi, kırılma tokluğu ve özgül kırılma enerjisi olmak üzere üç kırılma parametresi elde edilmiştir. Genel olarak, sonuçlar kırılma parametrelerinin yoğunluktan güçlü bir şekilde etkilendiğini göstermiştir. Yüksek yoğunluğa sahip çatlak ucu konumları, çatlak başlangıcına karşı daha dirençli görülmüştür. Yük-deformasyon eğrisinin ilk eğimi, ahşaptaki çatlak yoğunluğu arttıkça artmıştır. Regresyon analizi sonucunda yoğunluk ile her bir kırılma parametresi arasında pozitif ve güçlü korelasyonların olduğu gözlemlenmiştir.

Anahtar Kelimeler

Kırılma, Kırılma tokluğu, Güney sarıçam, Özgül kırılma enerjisi, Başlangıç eğimi

Kaynakça

• Ashby, M.F., Easterling, K.E., Harrysson, R., Maiti, S.K., 1985. The fracture and toughness of woods. Proceedings of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, 398(1815): 261–280.
• ASTM-D 2395-14, 2014. Standard test method for density and specific gravity (relative density) of wood and wood-based materials. Annual Book of ASTM Standards, USA.
• ASTM-E 399-09, 2009. Standard test method for linear-elastic plane-strain fracture toughness KIC of metallic materials. Annual Book of ASTM Standards, USA.
• Conrad, M.P.C., Smith, G.D., Fernlund, G., 2003. Fracture of solid wood: A review of structure and properties at different length scales. Wood and Fiber Science, 35(4): 570–584.
• Fruhmann, K., Reiterer, A., Tschegg, E.K., Stanzl-Tschegg, S.S., 2002. Fracture characteristics of wood under mode I, mode II and mode III loading. Philosophical Magazine A, 82(17-18): 3289-3298.
• Konukcu, A.C., Quin, F., Zhang, J., 2021. Effect of growth rings on fracture toughness of wood. European Journal of Wood and Wood Products, 79(6): 1495-1506.
• Kretschmann, D.E., Green, D.W., Malinauskas, V., 1991. Effect of moisture content on stress intensity factors in southern pine. Proceedings of International Timber Engineering Conference, 2-5 September, London, England, pp. 3.391-3.398.
• Majano, M.A.M., Hughes, M., Fernández-Cabo, J.L., 2010. A fracture mechanics study of thermally modified beech for structural applications. 11th World Conference on Timber Engineering (WCTE 2010), 20-24 June, Trentino, Italy, pp. 2103-2108.
• Ohuchi, T., Hermawan, A., Fujimoto, N., 2011. Basic studies on fracture toughness of sugi and acoustic emission. Journal of the Faculty of Agriculture Kyushu University, 56(1): 99-102.
• Patton-Mallory, M., Cramer, S.M., 1987. Fracture mechanics: A tool for predicting wood component strength. Forest Products Journal, 37(7/8): 39-47.
• Petterson, R.W., Bodig, J., 1983. Prediction of fracture toughness of conifers. Wood Fiber Science, 15(4): 302-316.
• Reiterer, A., Sinn, G., Stanzl-Tschegg, S.E., 2002. Fracture characteristics of different wood species under mode I loading perpendicular to the grain. Materials Science and Engineering: A, 332(1-2): 29-36.
• Reiterer, A., Tschegg, S., 2002. The influence of moisture content on the mode I fracture behaviour of sprucewood. Journal of Materials Science, 37(20): 4487-4491.
• Schniewind, A.P., Ohgama, T., Aoki, T., Yamada, T., 1982. Effect of specific gravity, moisture content and temperature on fracture toughness of wood. Wood Science, 15(2): 101-109.
• Smith, I., Landis, E., Gong, M., 2003. Fracture and Fatigue in Wood. John Wiley and Sons, England.
• Tukiainen, P., Hughes, M. 2016. The effect of temperature and moisture content on the fracture behaviour of spruce and birch. Holzforschung, 70(4): 369-376.
• Valentin, G., Adjanohoun, G., 1992. Applicability of classical isotropic fracture mechanics specimens to wood crack propagation studies. Materials and Structures, 25(1): 3-13.
• Vasic, S., 2000. Applications of fracture mechanics to wood. PhD Dissertation, The University of New Brunswick, Canada.
• Wu, Y., Shao, Z., Wang, F., 2012. Study on wood fracture parallel to the grains based on fractal geometry. International Journal of Fracture, 176(2): 163-169.
• Yoshihara, H., Usuki, A., 2011. Mode I critical stress intensity factor of wood and medium-density fiberboard measured by compact tension test. Holzforschung, 65(5): 729-735.