Avaliação da resistência ao cisalhamento à compressão e à torção de juntas coladas de pinus confeccionadas com diferentes ângulos e unidas com adesivo poliuretano

Abstract

Glued Laminated Wood is a technology based on the formation of structural pieces of wood joined together with adhesive. In the context of permanent or long-term structural use, applying this technology makes it possible to mitigate carbon emissions into the atmosphere, generating carbon trapping in the executed structures. The environmental benefits associated with the use of reforestation wood can be highlighted as well. With emphasis on the structural use of wood, the present work evaluated the adhesion quality of glued joints with different angles between the wood fibers, which were manufactured with Pinus sp. wood and joined with a bicomponent polyurethane vegetable-oil-based adhesive. The glued joints were produced with angles of 0°, 10°, 20°, 30°, 45°, 60°, 70°, 80° and 90° and evaluated in shear stress failure by compression and shear by torsion. When submitted to regression analysis, the values obtained for shear strength in compression showed a curve compatible with Hankinson's formula, with an R² value close to 0.76; however, the results for torsional shear showed R² values close to 0.17. Thus, Hankinson's formula turned out inadequate as an estimator of shear strength under torsion. The specimens showed different mechanical response to shear when tested in compression compared to those tested in torsion.