Micromechanical finite element modeling of moisture diffusion in unidirectional composite materials

Durability of composite materials has been affected by long-term exposure at moisture absorption. Interphase region plays an important role in the performance of composite materials. A micromechanical study of moisture absorption behavior of an E-glass/Epoxy unidirectional composite material is performed. The numerical model is based on mass diffusion analysis in ABAQUS software to investigate the effect of fiber arrangement and interphase thickness on saturation time. A typical microstructure of dimension 54μm×54μm with fiber of 18μm diameter is generated and for all models 4-node linear quadrilateral element (DC2D4) has been used. Each node has a single degree of freedom of moisture concentration. Results show that the fiber arrangement and interphase size has the great effect on the moisture kinetics. For interphase size of 6μm the saturation time decreases by 32% compared to the reference state (without interphase). Also, the finite element results are in a good agreement with Fick’s analytical model.