Continuum Modeling of Engineering Constants of Oriented Strandboard


  • Jong N. Lee
  • Qinglin Wu


Flake alignment distribution, in-plane modulus, laminate modeling, linear expansion co-efficient, structural panel


A two-dimensional model to predict engineering constants of oriented strandboard (OSB) was developed using a continuum theory. The orthotropic flake properties, flake alignment distribution, and panel shelling ratio (as measured by flake weight ratio, FWR, between face layer and entire board) for three-layer OSB were considered in the model.

The two-term cosine probability density function (PDF) provided an effective way to describe flake alignment distributions for both single and three-layer OSB based on flake angle measurements from the panel top surface. The parameters that define the PDF varied with percent alignment (PA) and FWR. The continuum model, combined with flake alignment PDFs, predicted general trends of changes in OSB's engineering constants including Young's moduli, shear modulus, Poisson ratio, and linear expansion (LE) coefficients. The predicted values Young's moduli and LE along the two major directions compared well with experimental data for selected board structures. The three-dimensional mesh plots on various properties allow examining the trend of change of each property as a function of PA and FWR, which can be used to optimize OSB's engineering performance.

The continuum model provides a comprehensive analytical solution for the prediction of two-dimensional engineering constants of OSB, which is the basis for future modeling on OSB's void structure.


Agarwal, B. D., and L. J. Broutman. 1990. Analysis and performance of fiber composites, 2nd ed. Wiley Interscience Publ., New York, NY. 449 pp.nBarnrs, D. 2000. Integrated model of the effect of processing parameters on the strength properties of oriented strand wood products. Forest Prod. J. 50(11/12):33-42.nBodig, J., and B. A. Jayne. 1982. Mechanics of wood and wood composites. Van Nostrand Reinhold Company, New York, NY. 712 pp.nChin, W., H. T. Liu, and Y. D. Lee. 1988. Effects of fiber length and orientation distribution on the elastic modulus of short fiber reinforced thermoplastics. Polymer Composites 9(1):27-35.nDai, C., and P. R. Steiner. 1994a. Spatial structure of wood composites in relation to processing and performance characteristics. Part 2. Modeling and simulation of a randomly-formed strand layer network. Wood Sci. Technol. 28(2):135-146.nDai, C., and P. R. Steiner. 1994. Spatial structure of wood composites in relation to processing and performance characteristics. Part 3. Modeling the formation of multilayered random strand mat. Wood Sci. Technol. 28(3):229-239.nGeimer, R. L. 1976. Flake alignment in particleboard as affected by machine variables and particle geometry. Research Paper FPL 275. USDA Forest Service, Forest Products Lab., Madison, WI.nGeimer, R. L. 1979. Data basic to the engineering design of reconstituted flakeboard. Pages 105-125 in T. M. Maloney, ed. Proc. 13th WSU International Symposium on particleboard. Washington State University, Pullman, WA.nGeimer, R. L., R. J. Mahoney, S. P. Loehnertz, and R. W. Meyer. 1985. Influence of processing-induced damage on strength of flakes and flakboards. Research Paper FPL 463. USDA Forest Service, Forest Products Lab., Madison, WI.nHalpin, J. C., and S. W. Tsai. 1969. Effects of environmental factors on composite materials. AFML-TR 67-423.nHarris, R. A., and J. A. Johnson. 1982. Characterization of flake orientation in flakeboard by the von Mises probability distribution. Wood Fiber 14(4):254-266.nHunt, M. O., and S. K. Suddarth. 1974. Prediction of elastic constants of particleboard. Forest Prod. J. 24(5):52-57.nJanowiak, J. J., D. P. Hindman, and H. B. Manbeck. 2001. Orthotropic behavior of lumber composite materials. Wood Fiber Sci. 33(4):580-594.nJones, R. M. 1975. Mechanics of composite materials. McGraw-Hill, New York, NY. 365 pp.nKelly, M. W. 1977. Critical literature review of relationships between processing parameters and physical properties of particleboard. Gen. Tech. Rept. FPL-10. USDA Forest Serv., Forest Products Lab., Madison, WI. 65 pp.nLee, J. N., and Q. Wu. 2002. In-plane dimensional stability of three-layer oriented strandboard. Wood Fiber Sci. 34(1):77-95.nLu, W., L. A. Carlsson, and Y. Andersson. 1995. Micro-model of Paper: part 1. Bounds on elastic properties. TAPPI J. 78(12):155-164.nPrice, E. W. 1976. Determining tensile properties of sweetgum veneer Hakes. Forest Prod. J. 26(10):50-53.nSalmen, N. L., and M. Rigdahi. 1985. Modeling exten-sional stiffness for different paper structure. TAPPI. 68(2):105-109.nScala, E. 1973. Composite materials for combined functions. Haden Book Company, Inc., Rochelle Park, NJ.nSchulgasser, K. 1985. Fiber orientation in machine-made paper. J. Mater. Sci. 20:859-866.nScala, E., and D. H. Page. 1988. The influence of transverse fiber properties on the in-plane elastic behavior of paper. Composite Sci. Technol. 32:279-292.nShaler, S. M., and P. R. Blankenhorn. 1990. Composite model prediction of elastic moduli for flakeboard. Wood Fiber Sci. 22(3):246-261.nSteinmetz, P. E., and C. W. Polley. 1974. Influence of fiber alignment of stiffness and dimensional stability of high-density dry-formed hardboard. Forest Prod. J. 24(5):45-50.nTsai, S. W., and H. T. Hahn. 1980. Introduction to composite materials. Technomic, CT.nUSDA Forest Service. 1987. 1997. Wood handbook: Wood as an engineering material. Agric. Handb. No. 72. USDA Forest Prod. Lab., Madison, WI. 466 pp.nWu, Q. 1999. In-plane dimensional stability of oriented strand panel: Effect of processing variables. Wood Fiber Sci. 31(1):28-40.nWu, Q., and O. Suchsland. 1996. Linear expansion and its relationship to moisture content change for commercial oriented strand boards. Forest Prod. J. 46(11/12):79-83.nXu, W. 2000. Influence of percent alignment and shelling ratio on linear expansion of oriented strandboard: A model investigation. Forest Prod. J. 50(7/8):88-93.nXu, W., and Otto Suchsland. 1997. Linear expansion of wood composites: A model. Wood Fiber Sci. 29(3):272-281.n






Research Contributions