Resumo

SOTOMAYOR CASTELLANOS, Javier Ramón; MACEDO ALQUICIRA, Isarael  e  CHAVEZ GARCIA, Hugo Luis. Variability in Densities, Ultrasound Speeds and Dynamic Modulus in Three Mexican and Three Japanese Woods. Ing. Desarro. [online]. 2020, vol.38, n.2, pp.382-399.  Epub 22-Out-2021. ISSN 0122-3461.  https://doi.org/10.14482/inde.38.2.624.15.

The variability in the experimental values of the density, the speed of ultrasound, and the dynamic modulus may be associated with the effect of the intrinsic properties of wood, and they are different between species and their directions of anisotropy. To verify this hypothesis, the objective of the investigation was to determine these parameters in three Mexican woods: Pinus pseudostrobus, Tabebuia rosea, and Quercus spp; and from three Japanese woods: Paulownia tomentosa, Cryptomeria japonica, and Fagus crenata. Ultrasound tests were perfor med in the radial, tangential, and longitudinal directions, and the anisotropy relationships and wavelengths were determined. The values of the densities, the speeds of ultrasound, and the dynamic modules for the woods of P. pseudos trobus, T. rosea, Quercus spp, P. tomentosa, C. japonica, and F. crenata present a wide and diverse range, both inter- and intra-species. This variability can be characterized with the coefficients of variation and determination. Ultrasound tests are useful for confirming the anisotropic character of ultrasound speed and modulus of elasticity of wood. For this, a sample size of 35 specimens oriented in the radial, tangential, and longitudinal directions is sufficient.

Palavras-chave : anisotropy; coefficient of determination; coefficient of variation; sample size; variability in wood; wavelength.

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