Dimensional stability of multi-layered wood-based panels: a review

The deformation of wood due to swelling and shrinkage induced by water absorption and desorption of cell wall components is still challenging the engineering of dimensionally stable multi-layer wood-based panels. To overcome this problem and to accelerate the developing process of new wood-based panels, numerical methods developed to describe the deformation stability of man-made composites could possibly be applied to wood materials too. Relevant influencing factors on the hygro-thermal deformation behaviour of wood are needed as input parameters for a numerical description of the material behaviour. These factors are collected and described. Moreover, an overview of empirical and numerical approaches is given and the mathematical description of the deformation behaviour is discussed. Numerical models are based on micromechanical theories, which consider the hygro-thermal deformation of composite materials. Micromechanical methods from composite mechanics applied to wood at different scale levels are examined. Challenges that may be considered when using micromechanical approaches to calculate the hygroscopical deformation of multi-layered materials are discussed.