Novel Test Method for Creep and Duration of Load Effects of Wood Products

The traditional test methods for evaluating creep as well as effects of load duration of wood have not resulted in a unifying theory of the closely related phenomena. The reason for this may be found in the actual test method. A new method for conducting stress relaxation is proposed. In contrast to creep tests, this method is a natural next step in the quest to understand long-term behaviour of wood. The new way of conducting long-term tests automatically gives control of the energy input to the tests, since, in a constrained deformation test, the load/stress will decrease/relax in case of material separation. This one feature is thought to give a reading of the behaviour of long-term failure in relation to stress-strain history. A test series for the fundamental cases of tension and bending of wood/wood products is to be performed at the Department of Building Technology and Structural Engineering, Aalborg University. The successful outcome of these tests will initiate a large-scale test series carried out in cooperation with BYG-DTU. The project is part of the Materials Research programme "Modelling the Effects of Moisture and Load History on the Mechanical Properties of Wood", funded by STVF and conducted in cooperation with The Technical University of Denmark (DTU).