Toughness and Impact Strength in Dynamic Bending of Wood as a Function of the Modulus of Elasticity and the Strength in Compression to the Grain

摘要

Toughness is the mechanical property that determines the wood strength when a force acts in a short time interval. Its value is determined in the bending impact test. Timber has to resist to impact forces in several applications, nevertheless this property is not widely studied to tropical wood species from Brazil. This study aimed to correlate the toughness and the impact strength of wood with the modulus of elasticity and the strength in the compression parallel to grain test. Therefore ten tropical species, from different strength classes, grown in Brazil were tested according to the Brazilian Standard Code ABNT NBR 7190:1997. The studied species were: Cedro (Cedrella sp.), Cambará Rosa (Erisma uncinatum Warm), Cedrorana (Cedrelinga cateniformis), Catanudo (Calophyllum sp.), Cupiúba (Goupia glabra), Angelim Saia (Parkia spp.), Tatajuba (Bagassa guianensis Aubl.), Guai?ara (Luetzelburgia sp.), Cumaru (Dipteryx odorata) and Angelim Vermelho (Dinizia excelsa Ducke). It was developed a relation between the studied properties through regression models, evaluated according to the variance analysis (ANOVA). The results of the statistical analysis revealed led to the conclusion that there is no correlation between the proposed properties for the analyzed species.