ASSESSING THE STRENGTH OF SHIPBUILDING WOOD IN WET ENVIRONMENT AND AT HIGH TEMPERATURES

Tóm tắt

Optimizing the spending energy in the naval structures is to decrease their weight. Thus, balsa wood plates are frequently used instead of solid plates because of their high stiffness-to-weight ratio. The mechanical properties of these materials can be significantly reduced by the presence of moisture inside them when they are exposed to a wet environment and high temperature. Thermogravimetric analyses under air atmosphere were performed on balsa wood to investigate the thermal degradation process of two types of samples aged differently: a dry balsa specimen and a hygroscopically aged material. The thermogravimetric method was used to determinate the kinetic parameters as the activation energy, the pre-exponnential factor and the order of reaction. The three constituents of balsa (i.e. hemicellulose, cellulose and lignin) were well identified and the decomposition temperature region well characterized. The presence of a large quantity of water affects the thermal decomposition behaviour of wood inducing notably a maximal degradation temperature.