Verification of Test Conditions to Determine the Compression Modulus of Elasticity of Wood

Abstract

The obtaining the modulus of elasticity in compression of the wood with the use of dial gauges, fixed on opposite faces of the specimens, may lead to deformation values and consequently to different elastic modulus as a function of the faces chosen for its attachment, being the timber an anisotropic material. This study aimed to evaluate the influence of two distinct positions for setting the dial gauges (A and B) in wood specimens tested in compression, using the assumptions of the test methods and calculation of the Brazilian standard ABNT NBR 7190: 1997. The woods evaluated in trials were the <i>Pinus elliottii</i> and <i>Corymbia citriodora</i>, being used seven specimens per species. A specimen was taken to the rupture, obtained the values of the maximum stress and strain (references) needed to obtain the elastic moduli of the six remaining specimens per species, certain non-destructively (two tests per piece). The results of analysis of variance revealed the equivalence between modules elasticity in compression parallel to the grain for both wood species investigated, resulting not significantly arrangement of dial gaugesto determine the properties of stiffness. However, the anisotropy of wood, these results cannot be extrapolated to other woods of the same or different species, justifying the setting of dial gauges in two different positions, allowing for judging whether or not the equivalence between the modulus of elasticity.