9. Investigation of the Hydric Transfer Phenomenon in Wood at the Ring Scale with the Grid Method

The water diffusion phenomenon and its effect on the deformation of wood samples are studied here. A suitable experimental device is designed to impose a direct contact on one side of the specimen with water. Strain maps are measured over time on the other side. The grid method is used for this purpose. White fir of Massif Central (Abies alba Mill) is studied here. During the experiments, strain gradients clearly appear between early and late woods, highlighting the different diffusion properties at the scale of the rings. The results also show changes in the moisture diffusivity of the material during the test. A cycle of adsorption/desorption is also studied. Results highlight the existence of residual strains at the wood ring scale.