Continuum Modeling of Engineering Constants of Oriented Strandboard
Keywords: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.
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