Changes in relative humidity cause temporal and spatial variations in the moisture content of wood, which may also affect the long-term mechanical response of timber structural elements. A review of existing studies have shown that different values of the moisture transport model parameters have been used in numerical analyses. Since the studies also differ in terms of other input data, boundary conditions and the analysed results, the influence of individual parameters cannot be directly compared across different analyses. Therefore, this master’s thesis investigates the influence of selected parameters of the multi-Fickian moisture transport model on the response of a simply supported timber beam. The ten-year response of the beam subjected to periodic variations in relative humidity between 50 and 65% was analysed. In each simulation, the value of one parameter was varied, while all other input data remained unchanged. The influence of the parameters was evaluated based on changes in the local and average moisture content and the mid-span deflection of the beam. The equations of the multiFickian moisture transport model and the three-dimensional mechanical model were solved numerically in a commercial software environment using the finite element method. The results show that the local and average moisture content are most strongly influenced by the sorption hysteresis parameters, while the average moisture content is also significantly affected by the flow resistance by the internal pore structure in the radial direction. The beam deflection is most strongly influenced by the sorption hysteresis parameters and the flow resistances by the internal pore structure in the radial and tangential directions. The results provide a basis for further research and enable the identification of parameters that require particular attention during the calibration of the numerical model.
|
