Simulation of drying stresses in wood -: Part II.: Convective air drying of sawn timber

This article describes a study where laboratory and theoretical work on the fundamental hygro-mechanical behaviour of wood is applied on convective drying of sawn timber. A material model describing the behaviour of wood during drying is used to simulate drying stresses in timber. Cross-sections containing heartwood, sapwood and a combination of both are studied. Simulations are compared with measurements from whole batches of sawn timber subjected to drying. The stress simulations show good agreement with the measurements. It is further shown how an alteration of a drying schedule changes the results in terms of internal stresses. Simulations of drying may be used to improve the quality of sawn timber and/or for optimising drying schedules. It is believed that simulations of drying instead of using trial and error tests on batches of sawn timber will prove to give economical and environmental benefits.