Multi-Scale Investigation of the Hygromechanical Behavior of Wood by X-Ray Microtomography and Digital Volume Correlation
Résumé
Swelling/shrinkage behavior of wood induced by relative humidity variations is anisotropic and influenced by its multi-scale and heterogeneous structure. In this study, 3D characterization of the structure and the hygromechanical behavior of earlywood, latewood and growth-ring samples is performed by X-ray microtomography. Samples are subjected to a relative humidity increase (44% to 97% RH) and imaged once they have reached their equilibrium moisture content. Digital volume correlation is used to measure the global and local strains. Earlywood and latewood exhibit different macroscopic hygromechanical behavior. Strains are not similarly distributed in the two types of wood. The local distribution of the strains related to the microstructure and interactions between earlywood and latewood are discussed.