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| Author(s): |
João Vítor Felippe Silva
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Guaratinguetá. 2023-03-02. |
| Institution: | Universidade Estadual Paulista (Unesp). Faculdade de Engenharia. Guaratinguetá |
| Defense date: | 2023-02-24 |
| Advisor: | Julio Cesar Molina |
| Abstract | |
The aim of this work was the numerical and experimental study of rolling shear stiffness (Gvt) and strength (fvt) of three layers Cross Laminated Timber (CLT) manufactured of wood from forests planted in Brazil and two-component polyurethane adhesive. Four wood species were used (Pinus elliottii, Eucalyptus grandis, Toona ciliata and Acrocarpus fraxinifolius), for CLT manufacturing. Initially, a bibliographic survey was carried out on the subject based on national and international available literature. Along with that the physical-mechanical characterization of the woods pieces and the evaluation of the manufacturing pressure were carried out for five pressure levels ranging from 0.1 MPa to 1.3 MPa. Rolling shear stiffness and strength were determined by three test methods: beam bending, vertical shear test piece and inclined shears. A numerical study was also carried out based on the finite element method (FEM) using ANSYS software; it was also developed a complementary analytical study using the “gamma”, “k” and “Kreuzinger” design methods available on the literature. The manufacturing pressure had no significant effect on the delamination percentage and thickness glue line of the CLT; however the strength in the glue line had a superior performance at the pressure of 0.7 MPa. The Gvt values obtained by the beam bending and inclined shear specimens methods were higher than those obtained by the vertical shear method. The three analyzed test models results of fvt were similar. The experimental failure modes were compatible with the stress distributions in the numerical models. The responses of the analytical methods differed significantly from each other, as the gamma method was the most sensitive to the stiffness and strength properties of CLT, which results were closer to the experimental ones. As main contributions of this work, it is recommended, for Brazilian reforestation woods with ρ12% between 380 kg/m3 and 480 kg/m3: the inclined shear specimen model for determination of stiffness and strength to rolling shear for CLT elements; the manufacturing pressure of at least 0.7 MPa; the “gamma” analytical method, and a total delamination limit of 10%. (AU) | |
| FAPESP's process: | 20/00555-6 - NUMERICAL AND EXPERIMENTAL STUDY OF THE MAIN PARAMETERS OF RESISTANCE AND STIFFNESS OF CROSS LAMINATED TIMBER ELEMENTS |
| Grantee: | João Vítor Felippe Silva |
| Support Opportunities: | Scholarships in Brazil - Doctorate |