Kızılçam odununda (Pinus brutia Ten. ) yorulma özelliklerinin belirlenmesi

Year 2015, Volume: 16 Issue: 1, 36 - 41, 09.04.2015

Ergün Güntekin Tuğba Yılmaz Aydın

Abstract

Bu çalışmada kızılçam (Pinus brutia Ten.) odunundan elde edilen kusursuz küçük örneklerde eğilme direncinin % 30, 40, 50, 60 ve 70 seviyelerinde 5 farklı gerilme, dakikada 15 ve 20 çevrim olmak üzere yorulma yükleri uygulanarak yorulma ömürleri bulunmuştur. Çalışma sonuçlarına göre kusursuz örneklerde %30 ve %40, yükleme seviyelerinde ortalama 1.000.000 üzeri tekrara ulaşmıştır. Genel olarak yükleme seviyesi (S) ile yorulma ömrü (N) arasında ters bir ilişki görülmektedir. Bu ilişki doğrusal olmayan regresyon yöntemiyle modellenmiştir. Log (N) = A * log (S) + B eşitlikleri ile kızılçamda yorulma ömrü tahmin edilebilir. Yorulma testleri uzun sürelerde yapılabildiği için bu çalışmada sadece dakikada 15 ve 20 yükleme kullanılmıştır. Frekansın daha sık ve geniş açıklıklarla uygulanmasıyla kızılçam odununda yorulma davranışı daha iyi anlaşılabilir.
Anahtar kelimeler: Kızılçam, Yorulma ömrü, Modelleme

Keywords

Kızılçam, Yorulma ömrü, Modelleme

Determination of fatigue properties for Turkish red pine (Pinus brutia Ten.)

Abstract

In this study, fatigue strength of red pine (Pinus brutia Ten.) wood was evaluated by applying 15 and 20 cycles per minute and 30% to 70% – 5 different load of static bending strength to small clear wood specimens. The study showed that fatigue life of Turkish red pine wood amounted over 1 million cycles when the stress level was 30 and 40%. In general, there is an inverse relationship between load level (S) and fatigue life (N). This relationship was modeled using nonlinear regression. Fatigue life of red pine wood can be predicted using the equation of Log (N) = A * log (S) + B. Since, fatigue tests are time consuming, only 15 and 20 cycles per minute frequencies were used in the study. By applying more and less frequent loading schemes, the fatigue behavior of red pine wood can be well understood.
Keywords: Turkish red pine wood, Fatigue life, Modelling

Keywords

Turkish red pine wood, Fatigue life, Modelling

References

• Ansell, M.P., 1995. Fatigue Design for Timber and Wood- Based Materials. Timber Engineering STEP 2: E22/1– E22/8.
• Bao, Z., Eckelman, C.A., 1995. Fatigue life and design stresses for wood composites used in furniture. Forest Product Journal, 45(7/8): 59-63.
• Bao, Z., Eckelman, C.A., Gibson, H., 1996. Fatigue strength and allowable design stresses for some wood composites used in furniture. Holz als Roh- und Werkstoff, 54: 377- 382.
• Bodig, J., Jayne, B.A., 1982. Mechanics of Wood and Wood Composites. Reinhold Company, New York.
• Bonfield, P.W., 1991. Fatigue evaluation of wood laminates for the design of wind turbine blades. PhD thesis, University of Bath, UK.
• Bonfield, P.W., Ansell, M.P., 1991. The fatigue properties of wood in tension compression and shear. Journal of Materials Science, 26: 4765–4773.
• Cai, Z., Bradtmueller, J.P., Hunt, M.O., Fridley K.J., Rosowsky, D.V., 1996. Fatigue behaviour of OSB in Shear. Forest Products Journal, 46(10): 81–86.
• Clorius, C.O., Pedersen, M.U., Hoffmeyer, P., Damkilde, L., 2000. Compressive fatigue in wood. Wood Science and Technology, 34: 21–37.
• Clorius, C.O., 2002. Fatigue in wood an investigation in tension perpendicular to the grain. PhD. Thesis, Danmarks Tekniske Universitet.
• Dai, L., Zhang, J., 2007. Fatigue performance of wood composites subjected to edgewise bending stresses. Forest Products Journal, 57(11): 44-51.
• Eckelman, C.A., 1987. Bending strength, fatigue strength, stiffness and allowable design stresses for engineered strand lumber, oriented strand lumber plus, and engineered strand panel, unpublished report. Department of Forestry and Natural Resources, Purdue University, West Lafayette.
• Hansen, L.P., 1991. Experimental investigation of fatigue properties of Engineering Conference, London, pp: 3742. wood beams. Timber
• Mcnatt, J.D., 1970. Design stress for hardboard – effect of rate, duration and repeated loading. Forest Products Journal, 20(1): 53-59.
• Thompson, R.J.H., Ansell, M.P., Bonfield, P.W., Dinwoodie J.M., 2002. Fatigue in wood-based panels. Part 1: The strength variability and fatigue performance of OSB Chipboard and MDF. Wood Science and Technology, 36: 255–269.
• Thompson, R.J., Bonfield, P.W., Dinwoodie, J.M., Ansell, M.P., 1996. Fatigue and creep in chipboard, Part 3, The effect of frequency. Wood Science and Technology, 30: 293–305.
• Tsai, K.T., Ansell M.P., 1990. The fatigue properties of wood in flexure. Journal of Material Science, 25: 865- 878.
• TS 24 2005. Odunun statik eğilme dayanımının tayini. TSE, Ankara.
• Zhang, J. Baozhen, C. And Daniewicz, S.R. 2005. Fatigue performance of wood-based composites as upholstered furniture frame stock. Forest Products Journal, 55(6):985-992.