Dielectric properties of continuous fiber reinforced polymer composites: Modeling, validation, and application

Microwave curing technologies can realize a fast and energy saving curing process with less temperature gradients in the composite thickness compared with traditional autoclave curing techniques. A fundamental understanding and quantitative characterization for the dielectric properties of composites are crucial steps to ensure an effective microwave curing process. Herein, this study aims at providing a practical method to predict the effective complex permittivity of continuous fiber reinforced composites. A stochastic method was used to simulate the real distribution of fibers in the resin matrix. The huge scale factor between the micro architecture and macro structure of composites was balanced by using homogenization methods. Then the dielectric properties of composites in both longitudinal and transverse directions were computed by finite element analysis. The effectiveness of the proposed model was validated by various experimental measurements. Statistical analysis showed that the relative error was only 1.48-3.17% between model calculations and experimental results. Based on curing kinetics, the proposed model was further applied to investigate the permittivity of composites during microwave cure. POLYM. COMPOS., 39:4646-4655, 2018. (c) 2017 Society of Plastics Engineers