Analysis of the deformation of wood during the drying process: An experimental approach

Deformations in samples can tell us more about internal stress in wood due to the drying process. This study deals with an approach to model and simulate the realistic deformations in wood samples during two laboratory drying devices. In order to minimize the sample preparation work and to avoid destroying parts of the drying batch by cutting out samples for prong or slicing tests, we want to predict the resulting deformation and therefore the drying quality concerning casehardening mathematically via the moisture distribution of the samples. This moisture distribution can by examined using the kilns moisture measurement equipment placing the electrodes in different depths over the cross section of a sample. Another positive effect could be that the moisture gradient over the cross section during the drying process may be traced as well. In the first studies we used beech wood and could predict the deformation (bending) of the prong samples fairly good. The used model for the deformation intensities is suitable for the convectional and the vacuum drying process, respectively. A good comparison between the realistic and simulated changes in deformation was found for both drying process. Further investigation shall prove the results for other wood species. © Forest Products Society 2015.