ABSTRACT
The objetive of this work was to determine the relation between the rigidity and strength properties in static bending and specific gravity of plywood manufactured from five veneers of Pinus elliottii Engelm from 30 year-old plantations. Linear simples, multiple and polynomial relations involving the modulus of rupture (MOR), modulus of elasticity (MOE), stress at proportional limit (TLP) and specific gravity (Me) of the plywood were studied. The specific gravity did not prove to be a very exact indicator of the rigidity and strength properties of the plywood. The MOE, MOR and TLP in static bending of the plywood showed low coefficients of correlations and determination adjusted for simple linear regression, indicating a little dependence of the specific gravity, the modulus of rupture in static bending on the principal directions (X and Y) had a strong dependence of the modulus of elasticity and stress at proportional limit. The coefficients of correlations of the best models of regression in the two directions varied from 0.85 to 0,91. The frequency histograms of the specific gravity of plywood showed a unimodal homogeneous distribution, while MOE and MOR showed a unimodal distribution with positive asymmetric skewness.
Key words:
Plywoods; veneer; static bending in plywood; Pinus elliottii