Prediction Model of Shrinkage Crack Propagation in Cross-Section of Timber Components

Abstract

Shrinkage cracks severely affect the safety of wood structures. Therefore, the moisture stress distribution of shrinkage cracks should be analyzed, and the interface crack depth of wood components predicted. In this paper, the equilibrium conditions, physical conditions, geometric conditions, and coordination equations of the disk humidity stress under a moisture content gradient Δw are deduced by referring to the elastic analytical solution model of temperature stress. Moreover, the humidity stress distribution equation is established, which is verified via the finite element method. The critical water content and shrinkage crack depth prediction models are further deduced based on the humidity stress distribution. The usability of the model is further verified using the test data of actual engineered wood components. The results demonstrate that the moisture stress is not determined by the initial moisture content Wi, equilibrium moisture content We, or member size but by moisture content gradient Δw. The shrinkage crack prediction model of wood components in cross-section can be applied to actual engineering prediction to provide a theoretical basis for the reinforcement measures and safety evaluation of wood structures.

Keywords

• wood components
• moisture content gradient
• humidity stress distribution
• shrinkage crack depth
• detection