The effect of temperature and moisture content on the mechanical behaviour of wood: a comprehensive model applied to drying and bending

摘要

This paper proposes a model able to simulate heat and mass transfer and mechanical behaviour of a wooden board during processing. The coupled heat and mass transfer equations are solved using an existing computational model named TransPore. From the moisture content and temperature profiles, a rigorous one-dimensional formulation and a relevant constitutive model are used to calculate the stress and strain evolution within the board due to shrinkage or external loading. This allows a fast, comprehensive and realistic model to be implemented. Used as a tool, it allowed us to gain new insights into industrial operations: 1. the post-drying storage stage instead of the drying operation by itself is responsible for the high risk of checking encountered when drying thick boards; 2. the hydro-thermal activation is of utmost importance in wood bending and subsequent shape freezing.