Random Field Representation of Horizontal Density Distribution in Partially Oriented Strandboard Mat
Keywords:
Random field, mathematical model, horizontal density distribution, auto-correlation function, partially oriented strandboard, von Mises distribution, uniform distribution, characteristic area, degree of orientationAbstract
A random field representation of the horizontal density distribution in partially oriented strandboard mats was investigated. The orientation of strands can be characterized by both the von Mises distribution and the uniform distribution within a range of angles. Theoretical models of the correlation coefficients of any two points simultaneously covered by one strand, characteristic area of the correlation, and the degree of orientation were developed. Results indicate that the concentration factor k = 700 is sufficiently large to represent a perfectly aligned strand arrangement in oriented strandboards based on the von Mises distribution. The correlation coefficients of two points in a mat have a lower bound (random case) and an upper bound (perfectly aligned) in both von Mises and uniform distributions. Based on the concept of characteristic area, where the minimum characteristic area is the area of the strand and the maximum characteristic area is approximate to the square of strand length, the degree of orientation in a panel can be represented as a function of characteristic area. This value is found to be very close to the percent alignment definition.References
Agterberg, F. P. 1974. Geomathematics: Athematical background and geo-science applications. Elsevier Scientific Publishing Co. Amsterdam, Netherlands. 596pp.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 flake mats. Wood Sci. Technol. 28:229-239.nDodson, C. T. J. 1971. Spatial variability and the theory of sampling in random fibrous networks. J. Roy. Stat. Soc., Series B, 33(1):82-94.nGeimer, R. L. 1976. Flake alignment in particleboard as affected by machine variables and particle geometry. Research Paper 275. USDA, Forest Products Lab., Madison, WI.nHarris, R. A. and J. A. Johnson. 1982. Characterization of flake orientation in flakeboard by the von Mises probability distribution function. Wood Fiber 14(4): 254-266.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.nLau, P. W. C. 1981. Numerical approach to predict the modulus of elasticity of oriented waferboard. Wood Sci. Technol. 14:73-85.nLu, C., P. R. Steiner, and F. Lam. 1998. Simulation study of wood-flake composite mat structures. Forest Prod. J. 48(5):89-93.nMardia, K. V. 1972. Statistics of directional data. Academic Press, London, U.K.nPfleiderer, S., D. G. A. Ball, and R. C. Bailey. 1993. AUTO: A computer determination of the two-dimensional autocorrelation function of digital images. Computers and Geosciences 19(6):825-829.nShaler, S. M. 1991. Comparing two measures of flake alignment. Wood Sci. Technol. 26:53-61.nSuchsland, O., and H. Xu. 1989. A simulation of the horizontal density distribution in a flakeboard. Forest Prod. J. 39(5):29-33.nTriche, M. H., and M. O. Hunt. 1993. Modeling of parallel-aligned wood strand composites. Forest Prod. J. 43(11/12):33-44.nVanmarcke, E. 1983. Random fields: Analysis and synthesis. The MIT Press, Cambridge, MA, London, U.K.nXu, W., and P. R. Steiner. 1995. A statistical characterization of the horizontal density distribution in flake-board. Wood Fiber Sci. 27(2):160-167.n
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