Xavier, José (2007) Characterisation of the wood stiffness variability within the stem by the virtual fields method : application to P.pinaster in the LR plane. PhD thesis Mécanique, ENSAM 2007ENAM0030 p.151.
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Official URL: http://home.utad.pt/~jmcx/
Abstract
In this work, an inverse approach for the identification of the LR stiffness parameters of maritime pine (P. pinaster) wood within the stem has been investigated. It is based on the application of the virtual fields method (VFM) to a rectangular specimen loaded with the Iosipescu fixture. This test has been designed in order to involve several in-plane stiffness components. The displacement fields have been measured by the grid method. The strain fields have been reconstructed from the measured displacement fields using a polynomial approximation scheme. The approach has been validated both numerically and experimentally. Two specimen configurations with grain at 0° and 45° have been compared. With the 0° configuration, only the Q11 and Q66 (longitudinal and shear stiffnesses) parameters have been identified with acceptable dispersion. The grain rotation of 45° has generated a redistribution of the strain fields allowing a better identification, namely for the Q22 (radial or transverse stiffness) parameter. The latter has been used in a subsequent study aiming at investigating the radial variability of the stiffnesses within the stem. It has been found that both Q22 and Q66 decrease from the pith to about the middle radius of the stem and increase afterwards to the outmost positions.
| Item Type: | PhD Thesis (PhD) |
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| Additional Information: | Document en anglais |
| Thesis Supervisor: | Pierron, Fabrice and Avril, Stéphane |
| Date: | 27 November 2007 |
| Board of examiners: | Marchal, Rémy and Gril, Joseph and Molimard, Jérôme and Avril, Stéphane and Morais, José and Pierron, Fabrice and Rouger, Frédéric |
| Ecole Doctorale: | ED 432 ECOLE DOCTORALE SCIENCES DES METIERS DE L'INGENIEUR |
| Discipline: | Mécanique |
| Collection (Fonds): | ENSAM |
| Institution: | ENSAM |
| Subjects: | 4. Materials Science, Mechanics and Mechanical Engineering |
| Uncontrolled Keywords: | Bois, essais d’Iosipescu, Identification, Mesure de champs, Méthode des champs virtuels, Full-field measurements, Parameter identification, Iosipescu test, Virtual fields method, Wood |
| ID Code: | 3177 |
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| Deposited By: | José Xavier |
| Deposited On: | 17 December 2007 |
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