Rheological behaviour of wood in directions perpendicular to the grain

The creep of wood in the grain direction is of major importance when deflections of structures are considered. Less studied is the creep in directions perpendicular to the grain, which is of interest when drying stresses and the cracking of wood are analysed. Experimental results obtained during 1987–1991 are reported. These included tensin, bending and some compression tests under constant and varying humidity at temperatures of 20–80°C. The results indicate that mechano-sorptive creep is still more important in directions perpendicular to the grain than in the longitudinal direction. Creep is also greatly dependent on the temperature.