Modeling of the viscoelastic mechano-sorptive behavior in wood

This paper focuses on the modeling of linearly viscoelastic, mechano-sorptive behavior and its effects during moisture content changes in timber. A generalized Kelvin-Voigt model integrating specific hygro-lock springs is developed and associated, in series, with a shrinkage-swelling element. The coupling between moisture content state and mechanical state implies an evolution in rheological parameters. This alternative approach leads to incorporating strain blockings during the drying period as well as memory effects during wetting phases after unloading. An incremental formulation is also established using a finite-element software, and, moreover, an experimental validation from tensile creep-recovery tests is presented.