Stress-strain relationships for spruce wood: Influence of strain rate, moisture content and loading direction
- 555 Downloads
The influence of strain rate, moisture content and loading direction on the stress-strain relationships for spruce wood has been investigated. The strain rates were approximately 8×10−3 s−1, 17s−1 and 1000 s−1, and the states of moisture content were those corresponding to oven dry, fiber saturated and fully saturated. Compressive loads were applied along the principal directions of the stem of the tree, i.e., radially, tangentially and axially. The low and medium strain-rate tests were performed with the aid of a servohydraulic testing machine, while the high strain-rate tests were carried out using the split Hopkinson pressure bar (SHPB) technique. Magnesium or steel bars were used in the different SHPB tests in order to reduce impedance mismatch for the different directions of the wood specimens. The strain rate was found to have large influence on the behavior of the wood, especially under the condition of full saturation, where water transport in the deforming specimen is of major importance.
Key WordsSpruce wood strain rate moisture content split Hopkinson thermomechanical pulping
Unable to display preview. Download preview PDF.
- 1.Uhmeier, A. andSalmén, L., “Influence of Strain Rate and Temperature on the Radial Compression Behaviour of Wet Spruce”,Journal of Engineering Materials and Technology,118,289–294 (1996).Google Scholar
- 2.Renaud, M., Rueff, M., andRocaboy, A.C., “Mechanical Behaviour of Saturated Wood under Compression. Part 1. Behaviour of Wood at High Rates of Strain”,Wood Science and Technology,30,153–164 (1996).Google Scholar
- 3.Renaud, M., Rueff, M., andRocaboy, A.C., “Mechanical Behaviour of Saturated Wood under Compression. Part 2. Behaviour of Wood at Low Rates of Strain, Some Effects of Compression on Wood Structure”,Wood Science and Technology,30,237–243, (1996).Google Scholar
- 4.Bragov, A. andLomunov, A.K., “Dynamic Properties of Some Wood Species”,Journal de Physique IV,7 (C3),487–492 (1997).Google Scholar
- 8.Stefanson, F., Mechanical Properties of Wood at Microstructural Level, Report TVSM-5057, M. Sc. diploma thesis, Lund Institute of Technology, Division of Structural Mechanics, Lund (1995).Google Scholar
- 9.Tabarsa, T. andChui, Y.H., “Stress-Strain Response of Wood under Radial Compression. Part I. Test Method and Influences of Cellular Properties”,Wood and Fiber Science,32, (2),144–152 (2000).Google Scholar
- 10.Tabarsa, T. andChui, Y.H., “Characterizing Microscopic Behavior of Wood under Transverse Compression. Part II. Effect of Species and Loading Direction”,Wood and Fiber Science,33 (2),223–232 (2001).Google Scholar
- 11.Dinwoodie, J.M., Timber, Its Nature and Behaviour, Van Nostrand Reinhold, New York, 50–67 (1981).Google Scholar
- 12.Sundholm, J., Papermaking Science and Technology, book 5: Mechanical Pulping, Fapet Oy, Helsinki, 34–65 (1999).Google Scholar
- 13.Dinwoodie, J.M., Papermaking Science and Technology, book 5: Mechanical Pulping, Fapet Oy, Helsinki, 90–104 (1999).Google Scholar