Wood Science and Technology 32 (Z998) 38Z-39Z © Springer-Verlag 1998
A continuum model of the interaction
between manufacturing variables
and consolidation of wood composite
A. Oudjehane, F. Lam, S. Avramidis
mats
.Abstract Wood composites produced using aspen flakes have displayed
interaction between manufacturing variables and stress-strain consolidation of
llhese mats. This study brings an original approach to the process of wood
composites within the analytical nonlinear continuum mechanics based model,
developed to predict the consolidation of wood mats during part of the hot-
]pressing cycle. Consolidation of wood flake mats occurred principally during the
closing of the press when the loose mat underwent uniaxial compression along its
perpendicular direction. Forming parameters such as mat thickness, and pressing
parameters such as'press closing rate, were accounted for in a combined
viscoelastic model with creep. The stress-strain consolidation model was applied
1:o different formed mat structures using random and oriented layout of flakes,
and although slightly higher values were obtained with the model regarding the
viscoelastic behavior of the loose mat, the creep model showed a very good
agreement with the experience data. These results within a continuum approach,
are significant in the manufacturing of wood composites as they would enable
optimization of manufacturing processes by integrating the specific conditions of
the forming process of wood mats into the pressing strategy.
I!ntroduction
Among the family of wood composites that includes a wide range of engineered
wood products like molded products, inorganic-bonded products and lumber or
timber products, wood panels are produced with discontinuous wood elements
such as particles, flakes, and strands. These wood panels result from the hot-
pressing of a loose mat formed by wood particles blended with an adhesive into
a continuous consolidated composite material. Thus, their properties depend
not only on the wood component properties, but the manufacturing process as
well.
381
Received 20 June 1997
A. Oudiehane, F. Lam, S. Avramidis
Wood Science Department, Faculty of Forestry,
University of British Columbia, 2424 Main Mall,
Vancouver, BC, Canada, V6T 1Z4
Correspondence to: A. Oudiehane
This project is financially supported by a Natural Sciences and
Engineering Research Council of Canada Strategic Grant (STR
0167246).