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Ciência Rural

versão impressa ISSN 0103-8478versão On-line ISSN 1678-4596

Resumo

MISSIO, André Luiz et al. Mechanical properties of Pinus elliottii tapped wood. Cienc. Rural [online]. 2015, vol.45, n.8, pp.1432-1438.  Epub 14-Abr-2015. ISSN 1678-4596.  https://doi.org/10.1590/0103-8478cr20130475.

The mechanical properties for static bending of Pinus elliottiitapped wood were evaluated by nondestructive and destructive tests. To achieve this, samples measuring 10x10x200mm3 (thickness, width and length) were prepared considering two factors: wood (juvenile, near to pith and mature, near to bark) and rosin, i.e., samples from logs with and without tapping grooves. The nondestructive evaluation were performed using an ultrasound equipment with dry-point transducers in order to measure the ultrasonic velocity and, consequently, the dynamic modulus of elasticity (ED). The modulus of elasticity (MOE) and the modulus of rupture (MOR) were measured through static bending tests. The wood brittleness were determined through the analysis of force x deformation plots. The results confirmed the significance of wood factor for the properties analyzed and the factor rosin, especially for MOR and density. The brittleness increased for the juvenile wood and, when included the factor rosin, this property tends to increase for the mature wood. The multiple regression model with Dummies variables proposed to estimate MOE as a function of ED was significant at 1% of probability of error (r2=0.75). Moreover, the results showed that factor wood and factor rosin did not negatively affect the mechanical properties of Pinus elliottiwood. In general, the timber from tapped logs could not represent significant damages when in structural service

Palavras-chave : Slash pine; pine resin; static bending; nondestructive method; dummies.

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