Fatigue and Hysteresis Effects in Wood-Based Panels Under Cyclic Shear Load Through Thickness
Keywords:
Energy loss, fatigue life, fatigue limit, shear through thickness, wood-based panelAbstract
The fatigue behavior of wood-based panels (plywood: PW, and oriented strandboard: OSB) under cyclic shear load through the thickness was experimentally investigated. Test specimens were cut into sections of 350-mm length and 240-mm width. Pulsating shear load through the thickness was applied along the length of specimens at stress levels corresponding to 60%~100% of static strength. The hysteresis loops of stress-strain curves were determined by measuring the shear load and the shear strain at the center of the specimen surface throughout the fatigue tests. The area enclosed by a hysteresis loop was defined as the energy loss per cycle, and was obtained for each loading cycle. To discuss the fatigue properties of wood-based panels under shear load through the thickness, the energy loss per cycle was examined in relation to the number of loading cycles. The energy loss per cycle at each stress level showed an almost constant value throughout most of the fatigue life, that is, from 5~10 loading cycles to just before fatigue failure. A significant correlation between energy loss during 5~10 loading cycles and fatigue life was obtained. Therefore, fatigue life could be predicted by monitoring energy loss in the cyclic shear-through-thickness test with approximately 10 loading cycles. As fatigue life lengthened, mean energy loss per cycle was found to decrease and seemed to gradually approach a threshold value. The stress level at which mean energy loss per cycle is equal to the threshold value can be regarded as the fatigue limit. A model equation for the relationship between mean energy loss per cycle and fatigue life was proposed and fitted to the data obtained. The threshold values of mean energy loss per cycle for PW and OSB were found to be 0.446 and 0.350 [kJ/m3/cycle], respectively. The fatigue limit was estimated to be approximately 40% of the static strength for PW and OSB, respectively, on the basis of the nonlinear relationship between mean energy loss per cycle and stress level.References
ASTM D2719. 2001. Standard test method of structural panels in shear through-the-thickness. Section-7, Vol. 04.10. Wood. 399-402. American Society for Testing and Materials, West Conshohocken, PA.nBao, Z., and C. A. Eckelman. 1995. Fatigue life and design stresses for wood composites used in furniture. Forest Prod. J.45(7/8):59-63.nBao, Z., C. A. Eckelman., and H. Gibson. 1996. Fatigue strength and allowable design stresses for some wood composites used in furniture. Holz Roh- Werkst.54:377-382.nBonfield, P. W., C. L. Hacker, M. P. Ansell, and J. M. Dinwoodie. 1994. Fatigue and creep of chipboard. Part 1, Fatigue at R = 0.01. Wood Sci. Technol.28:423-435.nFalk, R. H., D. Vos, and S. M. Cramer. 1999. The comparative performance of woodfiber-plastic and wood-based panels. Pages 269-274 in Proc. Fifth International Conference on Woodfiber-Plastic Composites.nHacker, C. L., and M. P. Ansell. 2001. Fatigue damage and hysteresis in wood-epoxy laminates. J. Mater. Sci.36:609-621.nGong, M., and I. Smith. 2003. Effect of waveform and loading sequence on low-cycle compressive fatigue life of spruce. J. Mater. Civil. Eng.15(1):93-99.nKohara, M., and T. Okuyama. 1993. Mechanical responses of wood to repeated loading VI—Energy-loss partitioning scheme to predict tensile fatigue lifetime. Mokuzai Gakkaishi39(11):1226-1230.nLee, A. W. C., and C. B. Stephens. 1988. Comparative shear strength of seven types of wood composite panels at high and medium relative humidity conditions. Forest Prod. J.38(3):49-52.nMarsoem, S. N., P. A. Bordonné, and T. Okuyama. 1987. Mechanical responses of wood to repeated loading II—Effect of wave form on tensile fatigue. Mokuzai Gakkaishi33(5):354-360.nOkuyama, T., and S. N. Marsoem. 1987. Mechanical responses of wood to repeated loading IV—Temperature-rises due to energy-loss. Mokuzai Gakkaishi33(11): 844-850.nOkuyama, T., A. Itoh, and S. N. Marsoem. 1984. Mechanical responses of wood to repeated loading I—Tensile and compressive fatigue fractures. Mokuzai Gakkaishi30(10):791-798.nPritchard, J., M. P. Ansell, R. J. H. Thompson, and P. W. Bonfield. 2001a. Effect of two relative humidity environments on the performance properties of MDF, OSB, and chipboard. Part 1. MOR, MOE and fatigue life performance. Wood Sci. Technol.35:395-403.nPritchard, J., M. P. Ansell, R. J. H. Thompson, and P. W. Bonfield. 2001b. Effect of two relative humidity environments on the performance properties of MDF, OSB, and chipboard. Part 2. Fatigue and creep performance. Wood Sci. Technol.35:405-423.nSasaki, Y., M. Yamasaki, and T. Sugimoto. 2005. Fatigue damage in wood under pulsating multiaxial-combined loading. Wood Fiber Sci.37(2):232-241.nShrestha, D. 1999. Shear properties tests of oriented strandboard panels. Forest Prod. J.49(10):41-46.nSuzuki, S., and H. Miyagawa. 2003. Effect of element type on the internal bond quality of wood-based panels determined by three methods. J. Wood Sci.49:513-518.nSuzuki, S., D. Nawa, K. Miyamoto, and T. Shibusawa. 2000. Shear-through-thickness properties of wood-based panels determined by the two-rail shear and the edgewise shear methods. J. Soc. Mat. Sci. Jpn.49(4):395-400.nThompson, R. J. H, M. P. Ansell, P. W. Bonfield, and J. M. Dinwoodie. 2002. Fatigue in wood-based panels. Part 1: The strength variability and fatigue performance of OSB, chipboard and MDF. Wood Sci. Technol.36:255-269.n
Downloads
Published
Issue
Section
License
The copyright of an article published in Wood and Fiber Science is transferred to the Society of Wood Science and Technology (for U. S. Government employees: to the extent transferable), effective if and when the article is accepted for publication. This transfer grants the Society of Wood Science and Technology permission to republish all or any part of the article in any form, e.g., reprints for sale, microfiche, proceedings, etc. However, the authors reserve the following as set forth in the Copyright Law:
1. All proprietary rights other than copyright, such as patent rights.
2. The right to grant or refuse permission to third parties to republish all or part of the article or translations thereof. In the case of whole articles, such third parties must obtain Society of Wood Science and Technology written permission as well. However, the Society may grant rights with respect to Journal issues as a whole.
3. The right to use all or part of this article in future works of their own, such as lectures, press releases, reviews, text books, or reprint books.
