Analysis of stress development during kiln drying of beech timber

Abstract Before use, timber must have reduced moisture content. Kiln drying causes cracking risk. This study aims to evaluate the risk of during beech wood samples using response surface methodology. Additionally, we aim develop an empirical model that describes critical tensile stress early stages and air parameters commonly used in kiln-drying schedules for timber, specifically, effects dry-bulb temperature (DBT) wet-bulb depression (WBD). Nine options conditions were analyzed according Central Composite Design assumptions; they combinations three DBT (30, 40, 50 °C) WBD (4, 5, 6 °C). During experiments, tangential shrinkage was completely restrained with a load cell measured generated stresses. The results ANOVA analysis confirmed is only factor significantly influencing at failure ( σ f ). second-order effect between has also been confirmed. condition causing highest shown multiple contour plots stresses content MC Reliability theory predict tissue. dependence tissue on conditions. When equal 30 °C, increases as relative humidity (RH) decreases. However, decreasing RH range corresponding increase from 4 °C reduces risk, which indicated by lower ) samples. Graphical