MOISTURE DRIVEN DAMAGE GROWTH IN WOOD MATERIAL : 3D IMAGE ANALYSIS FOR VISCOELASTIC NUMERICAL MODEL VALIDATION
Résumé
The viscoelastic behavior of wood under moisture content variation, known as mechano-sorption, induces different responses in the drying and the humidification phase. However, in presence of climatic variations, long-term loading and crack initiation, the mechanical behavior of wooden structures is highly modified, disturbing their implementation and shortening their life in service. In a combined experimental, numerical, and 3D image analysis approach, damage onset and propagation in samples from tropical Pterocarpus soyauxii (Padouk) due to climatic changes are investigated. The rupture in mixed mode coupling mechanical and moisture loads for orthotropic materials such as wood is also studied. The analytical formulation of the energy release rate is introduced by the A-integral, which couples rupture in mixed mode, thermal effects and the pressure applied on the crack lips. The efficiency of the proposed model is justified by showing the evolution of energy release rate versus crack length and versus moisture variation for various configurations by means of X-ray Computed Tomography.
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