Composite model prediction of elastic moduli for flakeboard.

Abstract

The objective of this research was to develop a model to predict the flexural modulus of elasticity of oriented flakeboards. Variables incorporated into the model included flake geometry, flake orientation, density, resin content, and species. Verification of the model was accomplished by comparing predictions with flexural modulus of elasticity (MOE) values measured parallel and perpendicular to the flake alignment direction of 192 specimens made from two species ( Populus grandidentata , Michx. and Acer rubrum ) at 4 resin levels (3, 5, 7 and 9%) and 3 target densities (35, 42, and 52 pcf). Use of the longitudinal Halpin-Tsai equations in conjunction with measured and estimated wood and resin properties, predicted the moduli of aspen and red maple flakeboard specimens with a standard error of estimate of 93,985 psi, a coefficient of determination of 89.5%, and an average of 25% below experimental values. The statistical correlations were influenced by grouping of data using flake alignment direction and species. Important issues of vertical density gradient, inhomogeneities, and resin compatibility were not accounted for. The approach was easily computed and gave reasonably accurate predictions of elastic moduli of a single oriented flakeboard manufactured over a range of resin levels, density, alignment, flake geometry, and species conditions.