Effect of oscillating drying conditions on variations in the moisture content field inside wood boards

Abstract

Wood drying is an essential process in the wood industry. During drying, the stress developed in the boards can produce several defaults such as deformations and cracks. The use of oscillating drying conditions should reduce the drying stresses in boards by activating the mechanosorptive creep. The best way to apply this concept remains an open question in the scientific community. In this paper, the effect of oscillating conditions on variations in moisture content across the board thickness was studied using an analytical model and a numerical code, TransPore. In addition, mechanical consequences of variations in moisture content produced by oscillations were studied by non-symmetrical drying (flying wood) and loaded drying (cantilever beam test). Beech wood, the second most commonly kiln-dried hardwood after oak in France, was chosen for this study owing to its elevated shrinkage coefficient, and hence its elevated risk of drying defaults.

Keywords:

• Drying simulation
• flying wood
• mechanosorptive creep
• wood oscillating drying

Acknowledgements

This research is developed in partnership between a fundamental public research laboratory, LERFoB—Team Bois Biomatériaux Biomasse, and Institut Technologique FCBA. This work is a part of a PhD research, funded by Institut Technologique FCBA and ANRT (Association Nationale de la Recherche et de la Technologie).