Micromechanics modeling on the prediction of dielectric constant of polymer‐matrix composites considering inhomogeneity interaction

Abstract Predicting the dielectric constant of composites based on their component characteristics can accelerate the development of high‐energy storage dielectrics. In this work, to take into account the shape and interaction of randomly oriented inhomogeneities on the dielectric properties of composites, the orientation interaction model (OIM) initially used for composite stiffness prediction is adopted to predict the dielectric constant of composites. OIM applies to multi‐phase composites, and the inhomogeneities are approximated using ellipsoids in OIM. To verify the proposed model, some test data are adopted, and the model predictions match well with the test data. It is found that the inhomogeneity shape has a large influence on the dielectric constant of composites, and the influence increases with increase of the dielectric property difference between inhomogeneities and the matrix. The model captures that at the same inhomogeneity volume fraction, composites containing high aspect ratio inhomogeneities exhibit a high dielectric constant, and it shows penny‐shaped inhomogeneities perform better than cylindrical inhomogenities on increasing the dielectric constant of composites. Highlights The interaction among randomly oriented inhomogeneities is considered. Every parameter can be determined based on the microstructure of composites. The proposed model applies to multi‐phase composites.