Temperature dependence of moisture diffusion in woven epoxy-glass composites: A theoretical and experimental study

The diffusion of moisture in woven glass fiber/epoxy resin composite is investigated theoretically and experimentally. Experiments are performed on a neat epoxy material and woven glass-epoxy composites at three distinct temperatures. As expected, the temperature highly affected the transport of moisture. For data analysis, a new homogenized diffusion model based on the geometry of the weave is adopted. Assuming steady-state process and Arrhenius law dependence between diffusivity and temperature, a very good agreement is found between theoretical diffusion coefficients and experimental data. To complete the analysis and extend it to transient behavior, a 3D finite element framework is built. An acceptable but not perfect agreement between the 3D finite element model and the mass uptake is reported as discrepancies, which are due to effects not captured by the analytical model, are observed. Reasons for the discrepancies and the limitations of the approach are discussed and provided. It is concluded that the homogenization can be used to predict the diffusion coefficients but only provides a rough estimate of the time-varying mass uptake.