A Numerical Study on the Influence of Natural Varying Humidity on the Moisture State of Structural Timber Members

摘要

This paper presents numerical analyses of timber element exposed to natural varying humidity at constant temperature. For determination of moisture field in timber element a coupled Fickian model is applied. The coupled model accounts for both vapor transport in pores and bound water transport in wood tissue. These transport processes are modeled by individual transport equations following Fick's law. The transport equations are fully coupled by process of phase change from vapor to bound water or vice verse, i.e. sorption. Moisture state history influences relationship between moisture state of wood and air humidity, it must therefore be taken into account. In order to include history dependency a hysteresis model is used here. Presented here are numerical studies results for timber specimen exposed to daily and hourly cyclic variation of outside humidity of the air.