epoxy silica nano-composite material simulation

I am doing a project on simulation of electrical properties of epoxy-silica nano-composite material. The electrical properties include resistivity, loss tangent, relative permittivity, voltage and thermal breakdown, with the variation in concentration of silica fillers. The boundary conditions applied are similar to parallel plate capacitor i.e., upper surface is given an ac voltage, lower surface is grounded and the side boundaries are given periodic conditions.

After composing the domains of randomly placed silica nano-fillers in the epoxy matrix i am not able to find the relative permittivity of the whole composite material with change in both voltage and frequency.

I am able to attach only one reference paper.

But I am unable to attach the models that i have worked so far.

Thank you.:)