Transient multi-Fickian hygro-mechanical analysis of wood

A new hygro-mechanically coupled material model to simulate the structural behaviour of wooden objects below the fibre saturation area is introduced. A multi-Fickian moisture transport model is coupled to a moisture-dependent, orthotropic, elasto-plastic, mechanical material model. It is applied to wooden specimens at simulated climate changes of the ambient air and analysed by the finite element method with respect to internal stresses due to swelling and shrinkage. A simulation of the ductile failure of a swelling pressure experiment is presented. The results are compared to different, widely used moisture transport models. The importance of capturing water vapour diffusion inside the object and its emissivity at the objects' surface are discussed.