Mechano-sorptive effects on timber creep

Fick's law of predicting the moisture content of beams, combined with a simple mechano-sorptive model is applied to the analysis of creep resulting from moisture variations due to changing environmental conditions. The natural climatic conditions are modelled with the daily and annual cyclic variations represented by sine waves. As the moisture change responding to varying climatic conditions is always greater near the boundaries of a timber section, the creep rate close to the surface layer is higher than that in the middle of the cross-section. Therefore with time, an increased portion of the load will be carried by the inner part of the material.