Modeling of Moisture Diffusion in Carbon Braided Composites

摘要

In this study, we develop a methodology based on finite element analysis to predict theweight gain of carbon braided composite materials exposed to moisture. The analysis was basedon the analogy between thermal conduction and diffusion processes, which allowed for acommercial code for finite element analysis to be used. A detailed finite element model using arepetitive unit cell (RUC) was developed both for bundle and carbon braided composites.Conditioning tests were performed to estimate the diffusivity of both the resin and composite.When comparing numerical and experimental results, it was observed that the procedureintroduces an average error of 20% and a maximum error of 31% if the RUC is assumed to beisotropic. On the other hand, the average error does not exceed 10% and the maximum error isless than 20% when the material is considered as orthotropic. The procedure is independent ofthe particular fiber architecture and can be extended to other composites.