Micromechanical measurement of wood substructure properties.

Abstract

The annual rings of softwoods are visually obvious and represent cylindrical layers of primarily cellulosic material that possess significantly different properties. For simplicity, wood construction products are designed assuming a material homogeneity that does not exist. As rapidly grown plantation trees are used for wood products, fewer rings are contained in an individual wood product with the outcome of each individual ring playing a greater role in product structural performance. The magnitudes of these earlywood and latewood property differences are largely unknown because of the difficulty in measuring small specimens. A cooperative study between the University of Wisconsin-Madison and USDA FS Forest Products Laboratory is underway to quantify the impact of variations in earlywood and latewood proportions. This paper discusses the background, approach, device used to determine modulus of elasticity (E) and shear modulus (G) for earlywood and latewood, difficulties faced with testing wood, and presents preliminary results.

Citation

Kretschmann, David E.; Schmidt, Troy W.; Lakes, Roderic S.; Cramer, Steven M. 2002. Micromechanical measurement of wood substructure properties. Proceedings of the 2002 SEM Annual Conference & Exposition on Experimental and Applied Mechanics, June 10-12, 2002, Milwaukee, Wisconsin [electronic resource]. Bethel, CT : Society for Experimental Mechanics. c2002: [3] pages.