The Influence of Voids on the Engineering Constants of Oriented Strandboard: A Finite Element Model


  • Qinglin Wu
  • Jong N. Lee
  • Guangping Han


Finite element modeling, strand alignment level, in-plane elasticity, laminate model, linear expansion coefficient, structural strandboard, voids


A laminated model based on continuum theory combined with finite-element analysis (FEA) was used to predict the influence of voids on engineering constants of oriented strandboard (OSB). Cylindrical voids with three material density classes in the void region were considered at various void volume fractions (VVFs) and matrix anisotropies. It was found that the presence of voids resulted in substantial decreases in the elastic moduli and Poisson ratio of OSB. The hygroexpansion coefficients were affected little by voids. The elastic constants normalized with their void-free (matrix) values were found to depend little on the anisotropy of the matrix, especially at high VVFs. Increases of material density in the void region led to increases in predicted elastic constants. The predicted moduli values for the void models with certain material densities correlated well with available experimental data for the selected panel structures. The FEA provided a comprehensive numerical tool in predicting localized elastic properties of porous OSB. The model is the basis for modeling three-layer boards and for constructing in-plane modulus map of full-size panels.


Adams, D. F., and D. R. Doner. 1967. Transverse normal loading of a unidirectional composites. J. Composite Materials1:152-164.nANSYS. 2002. ANSYS 6.0 Online help. ANSYS Inc., Canonsburg, PA.'>, R. M., and K. H. Lo. 1979. Solution for effective shear properties in three phase sphere and cylinder models. J. Mech. Phys. Solids27:315-330.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. 1994b. 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.nGibson, L. T., and M. F. Ashby. 1988. Cellular solid—structure and properties. Pergamon, New York, NY.nHalpin, J. C., and S. W. Tasi. 1969. Effects of environmental factors on composite materials. AFML-TR 67-423.nHunt, M. O., and S. K. Suddarth. 1974. Prediction of elastic constants of particleboard. Forest Prod. J.24(5): 52-57.nJones, R. M. 1975. Mechanics of composite materials. McGraw-Hill, New York, NY. 355 pp.nLang, E. M., and M. P. Wolcott. 1996. A model for viscoelastic consolidation of wood-strand mats: Part I. Structural characterization of the mat via Monte Carlo simulation. Wood Fiber Sci.28(1):100-109.nLee, J. N., and Q. Wu. 2002. In-plane dimensional stability of three-layer oriented strandboard. Wood Fiber Sci.34(1):77-95.nLee, J. N., and Q. Wu. 2003. Continuum modeling of engineering constants of oriented strandboard. Wood Fiber Sci.35(1):24-40.nLenth, C. A., and F. A. Kamke. 1996. Investigations of flakeboard mat consolidation. Part I. Characterizing the cellular structure. Wood Fiber Sci.28(2):153-167.nShaler, S. M. 1986. The usefulness of selected polymer composite theories to predict the elastic moduli of orientated flakeboard. Ph.D. thesis, Pennsylvania State Uni., University Park, PA. 163 pp.nSubramanian, L. 1993. Analysis of the influence of voids on the hygroelastic properties of paper. M.S. thesis, Dept. of Mechanical Engineering, Florida Atlantic University, Boca Raton, FL. 164 pp.nSuchsland, O. 1962. The density distribution in flake-board. Q. Bull., Michigan Agric. Experiment Station, Michigan State Univ. 45(1):104-121.nSuchsland, O., and H. Xu. 1989. A simulation of the horizontal density distribution in a strandboard. Forest Prod. J.39(5):29-33.nWu, Q. 1999. In-plane dimensional stability of oriented strandboard panel: Effect of processing variables. Wood Fiber Sci.31(1):28-40.n






Research Contributions