Estimation of strength and stiffness in compression parallel to the grain of Pinus sp. by colorimetry

Abstract

Strength and stiffness properties of the wood, fundamental in a structural design, are determined based on mechanical tests. Among the mechanical properties of wood, the strength (f _c0 ) and stiffness (E _c0 ) to compression in the parallel direction to the grain. Color is a characteristic of each species. If the f _c0 and E _c0 properties of a wood species are determined experimentally, based on a significant number of characterized samples, the correlation of these properties through equations obtained by regression makes it possible to estimates of such properties without the need for new tests, a procedure with potential for application by companies of the wood industry. With the aid of the CIE L*a*b* system and 403 pieces of wood from Pinus sp. equations obtained by regression analysis were used to estimate the E _c0 and f _c0 as a function of colorimetric parameters and also the number of growth rings. From the estimate of E _c0 (R ² = 43.61%), by ANOVA of the regression equation, it was found significance only in the number of growth rings (Nle). For the compressive strength parallel to the grain (R ² = 48.53%), only the colorimetric parameters and the interactions of these parameters significantly affected the f _c0 .

Keywords:
Mechanical properties; Growth rings; Multiple regression