Hasan Hüseyin CIRITCIOĞLU, Ersin PAMUKÇU

Sığ Kriyojenik İşlemin Sarıçam (Pinus sylvestris L.) Odunu Eğilme Direnci ve Elastikiyet Modülü Üzerine Etkilerinin Araştırılması

Bu çalışmada farklı rutubet miktarına (RM) sahip (HK-Hava kurusu, LD- Lif doygunluğu ve SD- Suya doymuş) Sarıçam (Pinus sylvestris L.) odununa -70 oC’de sığ kriyojenik işlem (SKİ) uygulamanın ağaç malzemenin eğilme direnci ve elastikiyet modülü özelliklerindeki etkileri araştırılmıştır. Eğilme direncinin (ED) belirlenmesinde TS 2474, eğilmede elastikiyet modülünün (EEM) belirlenmesinde ise TS 2478 esaslarına uyulmuştur. SKİ uygulanması ile örneklerin ED ve EEM üzerinde kayda değer artışlar gözlenmiştir. Ayrıca SKİ uygulamanın ED ve EEM üzerindeki etkisi istatistiksel olarak anlamlı bulunmuştur (p≤0,05). Malzemelerin maruz kaldıkları RM arttıkça ED ve EEM değerlerinin düştüğü görülmüştür. RM’nin ED üzerindeki etkisi istatistiksel olarak anlamlı iken (p≤0,05), EEM üzerindeki etkisi anlamsız bulunmuştur. Çalışma sonucu en yüksek ED (101,16 N/mm2) - 70 oC SKİ uygulanmış HK rutubetindeki örneklerde görülürken en düşük ED (76,05 N/mm2) SKİ uygulanmamış SD örneklerde görülmüştür. Benzer şekilde en yüksek EEM (12629,2 N/mm2) SKİ uygulanmış HK rutubet miktarlı örneklere görülürken en düşük EEM (8759 N/mm2) SKİ uygulanmamış LD rutubet miktarına sahip örneklerde görülmüştür. Sonuç olarak SKİ uygulamanın ağaç malzemenin mekanik özellikleri üzerinde olumlu etkiye sahip olduğu söylenebilir.

Anahtar Kelimeler:

Ağaç modifikasyonu, Mekanik özellikler, Sarıçam, Sığ kriyojenik işlem

Investigation of the Effects of Shallow Cryogenic Treatment on Bending Strength and Modulus of Elasticity of Scots Pine (Pinus sylvestris L.)

In this study, the application of shallow cryogenic treatment (SCT) to the Scotch Pine wood (Pinus sylvestris L.) which has different moisture content (MC type; AD-air dry, FS-fiber saturation and WS-water-saturated) and effects on bending strength and modulus of elasticity properties were investigated. TS 2474 principles were used for determination of bending strength (BS) and TS 2478 principles were used for determination of modulus of elasticity (MOE). Significant increases in the BS and MOE of the samples were observed with the application of SCT. In addition, the effect of SCT on BS and MOE was found to be statistically significant (p≤0.05). It was observed that BS and MOE values decreased due to the increase in MC to which the materials were exposed. The effect of MC on BS was statistically significant (p≤0.05) and there was no statistically significant difference for MOE. As a result of the study, the highest BS (101,16 N/mm2) was observed in AD moisture content samples with -70 oC SCT, while the lowest BS (76,05 N/mm2) was observed in WS moisture content samples without SCT. Similarly, the highest MOE (12629,2 N/mm2) was observed in AD moisture content samples with -70 oC SCT, while the lowest MOE (8759 N/mm2) was observed in FS moisture content samples without SCT. As a result, it could be said that SCT application has a positive effect on the mechanical properties of wood material.

Keywords:

Wood modification, Mechanical properties, Scotch Pine, Shallow cryogenic treatment,

PDF

___

[1] L.C. Palka, "Predicting the effect of specific gravity, moisture content, temperature and strain rate on the elastic properties of softwoods," Wood Science and Technology, vol. 7, no. 2, pp. 127–141, 1973.
[2] R.E. Hernández, L. Passarini, A. Koubaa, "Effects of temperature and moisture content on selected wood mechanical properties involved in the chipping process," Wood Science and Technology, vol. 48, n. 6, pp. 1281–1301, 2014.
[3] S.V. Glass, S.L. Zelinka, "Moisture Relations and Physical Properties of Wood" in Centennial Edition Wood Handbook - Wood as an Engineering Material General Technical Report FPL: GTR-190, Madison, WI: US Dept. of Agriculture, Forest Service, Forest Products Laboratory, 2010, ch. 4, pp. 4.1-4.19.
[4] C.C. Gerhards, "Effect of moisture content and temperature on the mechanical properties of wood: an analysis of immediate effects," Wood and Fiber, vol. 14, n. 4, pp. 36, 1982.
[5] M. Arnold, "Effect of moisture on the bending properties of thermally modified beech and spruce," Journal of Materials Science, vol. 45, pp. 669–680, 2010.
[6] B. Richard, "Drying and Control of Moisture Content and Dimensional Changes" in Centennial Edition Wood Handbook - Wood as an Engineering Material General Technical Report FPL: GTR-190, Madison, WI: US Dept. of Agriculture, Forest Service, Forest Products Laboratory, 2010, ch. 13, pp. 13.1-13.20.
[7] N. Ayrilmis, Ü. Buyuksari ve N. As, "Bending strength and modulus of elasticity of wood-based panels at cold and moderate temperatures," Cold Regions Science and Technology, vol. 63 n. 1-2, pp. 40–43, 2010.
[8] L. Caetano, B. Galpin, V. Grolleau and J-D. Capdeville, "Behaviour of a birch plywood under various experimental conditions," EPJ Web of Conferences, vol. 94, p. 05010, 2015.
[9] L. Caetano, V. Grolleau, B. Galpin, A. Penin and J.D. Capdeville, "High strain rate out-of-plane compression of birch plywood from ambient to cryogenic temperatures," Strain, vol. 54, n.2, pp. 1-17, 2018.
[10] D.W. Green, J.W. Evans, J.D. Logan and W.J. Nelson, "Adjusting Modulus of Elasticity of Lumber for Changes in Temperature," Forest Product Journal, vol. 49, pp. 82–94, 1999.
[11] A. Mishiro, "Effect of freezing treatments on the bending properties of wood," Bulletin of the Tokyo University Forests, vol. 82, pp. 177–189, 1990.
[12] S. Gao, X. Wang and L. Wang, "Modeling temperature effect on dynamic modulus of elasticity of red pine (Pinus resinosa) in frozen and non-frozen states," Holzforschung, vol. 69, pp. 233–240, 2015.
[13] L. Zhao, J. Lu, Y. Zhou and J. Jiang, "Effect of low temperature cyclic treatments on modulus of elasticity of birch wood," BioResources, vol. 10, n. 2, pp. 2318–2327, 2015.
[14] A. Mishiro and I. Asano, "Mechanical properties of wood at low temperatures: Effect of moisture content and temperature of the bending properties of wood, 2: Moisture content beyond the fiber-saturation point," Mokuzai Gakkaishi-Journal of the Japan Wood Research Society, vol. 30, pp. 277–286, 1984.
[15] L. Zhao, J. Jiang, J. Lu and T. Zhan, "Flexural property of wood in low temperature environment," Cold Regions Science and Technology, vol. 116, pp. 65–69, 2015.
[16] R. A. Schmidt and J.W. Pomeroy, "Bending of a conifer branch at subfreezing temperatures: implications for snow interception," Canadian Journal of Forest Research, vol. 20, pp.1251–1253, 2008.
[17] L. Zhao, J. Jiang and J. Lu, "Effect of thermal expansion at low temperature on mechanical properties of Birch wood," Cold Regions Science and Technology, vol. 126, pp. 61–65, 2016.
[18] J.Y. Huang, Y.T. Zhu, X.Z. Liao, I.J. Beyerlein, M.A. Bourke and T.E. Mitchell, "Microstructure of cryogenic treated M2 tool steel," Materials Science and Engineering A, vol. 339, pp. 241–244, 2003.
[19] A. Akhbarizadeh, A. Shafyei and M.A. Golozar, "Effects of cryogenic treatment on wear behavior of D6 tool steel," Materials and Design, vol. 30, pp. 3259–3264, 2009.
[20] G. D. Kendra and J. Cortez, "Cryogenically treated wooden baseball bat," U.S. Patent 2010/0307170 A1, Dec. 9, 2010.
[21] TSE 2470. Odunda Fiziksel ve Meknaiksel Deneyler için Numune Alma Metotları ve Genel Özellikler. Ankara: Türk Standartları Enstitüsü; 1970.
[22] D. Green and J. Evans, "The Immediate Effect of Temperature on the Modulus of Elasticity of Green and Dry Lumber," Wood and Fiber Science, vol. 40, pp. 374–383, 2008.