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Reforestation wood is interesting for construction, due to its potential as material source for manufacturing. For this purpose, the Eucalyptus genus has resulted in a better characterization of the material properties. During the production process, wood is machined at some stage, which influences the wood gluing quality. This study considered the performance of Eucalyptus saligna wood joints bonded with four commercial polyvinyl-acetate-based resins with different physical characteristics and chemical compositions. The surfaces of samples were prepared and machined by an up-milling process, using a planer, with wood feed rates of 6 m/min, 11 m/min, 16 m/min, and 21 m/min, which had advances per tooth of 0.25 mm, 0.45 mm, 0.66 mm, and 0.87 mm, respectively. The samples were prepared for shear strength testing of the glue line. During the preparation, all pieces were randomly bonded with regards to the formation plans of wood growth rings. Shear strength values were statistically compared to analysis of variance and Tukey test. Only C4 adhesive reached good results at all feed rates as well as having the best shear strength compared to other resins. Commercial adhesives had distinct interactions on the adhesive-wood interface, which resulted in different adhesion strengths.

Made available in DSpace on 2020-12-12T01:31:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-01 A high-density particleboard composed of peanut shells (Arachis hypogaea L.), an agro-industrial residue, and bamboo wastes of the species Dendrocalamus giganteus (branches and apical part), bonded with a two-component polyurethane resin based on castor oil (Ricinus communis L.) in the proportion of 12% of the particleboard mass, was produced. Four types of specimens were prepared according to the percentage of peanut shells: 0%, 10%, 20%, and 30%. Mechanical characteristics were evaluated through the flexural strength tests for modulus of rupture, modulus of elasticity, perpendicular traction, and screw pull resistance. The particleboard reached an average density of 917.2 kg/m3, meaning that it could be classified as high-density particleboard. The results of the mechanical tests indicated that the specimens containing a mixture in the proportion of 90% bamboo and 10% peanut hull presented the best mechanical strength. The experiment produced particleboards with a satisfactory mechanical physical performance that met the standards ABNT NBR 14.810-2 and ANSI A208-1, supporting the use of the peanut shell residue in the manufacture of particleboards to be used in internal environments and allowing the applicability of this residue through additional value. Mechanical Engineering Department UNESP Unesp Univ Estadual Paulista, Avenida Luiz Edmundo Carrijo Coube Wood Industrial Engineering Department UNESP Univ Estadual Paulista, Rua Geraldo Alckmin Federal Institute of Paraná, Avenida Dr. Tito Mechanical Engineering Department UNESP Unesp Univ Estadual Paulista, Avenida Luiz Edmundo Carrijo Coube Wood Industrial Engineering Department UNESP Univ Estadual Paulista, Rua Geraldo Alckmin

In the current competitive market, production efficiency and product quality are prioritized by the whole industry. Machinery characterization is an understudied topic, particularly in those sectors focused on basic raw material production, processing, and/or heavy industrialization. For this reason, the wooden housing sector requires evaluation to identify its mechanical potential and support future policies dealing with industrial development. This study aimed to identify the equipment and machinery from Brazilian timber housing producers. Such a sectoral study involved individual personal data collection by way of face-to-face interviews. Sampled producers were asked about equipment/machinery size, drying process availability, and the range of overall obsolescence from these devices. Thus, tools, portable machines, and medium-sized machinery exhibited the highest popularities, revealing a lower industrial level. Most of these producers do not have machined drying processes because of the demand for static infrastructures. The low obsolescence was a result of the greater utilization of compact equipment, which is easier to replace because of its low cost. Lower-cost machinery could also stimulate in the creation of new businesses for this sector.

Wood is a natural material with great variability in its mechanical properties. This study analyzed the effectiveness of the impulse excitation technique (IET) to characterize the stiffness of 10-year-old Eucalyptus grandis wood at three different heights of 3 m, 6 m, and 9 m from the bottom (height A, B, and C, respectively). A nondestructive testing method—excitation impulse, using Sonelastic® PC-based technology—and a destructive static bending test were used. The mean value for the modulus of elasticity (MOE) in bending was 16.4 GPa and in IET the value was 16.6 GPa. The average values for MOE in static bending were 14.8 GPa at height A, 17.9 GPa at height B, and 17.0 GPa at height C, demonstrating that the greater the height in the trunk of the tree the greater its modulus of elasticity. The correlation equation between static MOE and dynamic MOE was MOESTAT = 0.743.MOEDYN + 4.0983, with the coefficient of determination of R² = 0.85.