A Stress Model for Lumber Drying Control

Rapid changes in lumber value and energy costs have forced concern for more efficient lumber drying and a higher quality end product. Computer automation provides a practical solution to this problem. Mathematical predictions of moisture loss and shrinkage induced stress are required for effective automation. In response to this need an elastic-plastic hysteresis stress model to predict stresses in boards during kiln drying was developed. The model prediction is compared to experimental data for release strain, set strain, prong deflection, and board failures.