BEHAVIOR CHARACTERISTICS OF A DUAL MATERIAL WOOD-COMPOSITE IN WET ENVIRONMENT

Tóm tắt

The objective of the aircraft and naval industries is the optimization of structures in terms of lightening and strength. Thus, dual material plates, consisting of a light core covered by face sheets, are frequently used instead of solid plates because of their high bending stiffness-to-weight ratio. However, the mechanical properties of these materials can be significantly reduced by presence of moisture inside them when they are exposed to a wet environment during long time service. In order to analyse the internal stresses induced due to moisture absorption in material, moisture absorption characteristic was investigated for specimens of a dual material wood-composite composed of E-glass/polyester face sheets bonded to a wood balsa. These specimens were immersed in distilled water at 40°C, and the weight gain was measured. The hygroscopic strains were measured for balsa wood specimens. A hydro-mechanical finite element model has been built and is used to simulate the moisture diffusion-induced internal stresses. The obtained results allow predict a multi-layer internal appearance stresses to determine the geometrical stability of the structure.