Electrical resistivity prediction of dry carbon fiber media as a function of thickness and fiber volume fraction combining empirical and analytical formulas

The transverse electrical resistivity of the dry unidirectional carbon fiber preforms was studied experimentally taking into consideration various parameters. The dependency of the electrical resistivity transverse to the fibers was thoroughly experimentally studied as a function of the preform thickness and the fiber volume fraction. Empirical mathematical relations were extracted and combined with a non-linear compaction semi-analytical formula. The extracted formula consolidates the compressibility of the preform material, the preform thickness and the fiber volume fraction or the applied pressure in order to calculate the electrical resistivity of the unidirectional preform material transverse to the fibers. Two electrical resistance measurements, at two different thicknesses and two electrical resistance measurements, at two different pressure levels, are necessary to obtained, in order to predict the full range of the electrical resistivity values of the preform material transverse to the fibers as a function of thickness and fiber volume fraction. Very good agreement between the proposed formulas and the experiments has been obtained.