Electromagnetic Shielding With CFRP Composites: Conducting Matrix Versus Conducting Fibers

Abstract

ABSTRACTCarbon fiber reinforced polymer (CFRP) composites are widely used in the aerospace industry. In order to render them opaque to incoming electromagnetic radiation, the current practice is to attach a thin woven or nonwoven metallic mesh with a suitable adhesive resin to the laminates. If the metal mesh is to be eliminated altogether, there are two competing strategies that can help increase the shielding effectiveness of CFRP laminates. Firstly, the isotropic electrical conductivity of the matrix can be improved by either adding conducting fillers or changing the matrix to one that is more conductive than epoxy. Secondly, the anisotropic conductivity of the individual carbon fibers or the carbon fabric can be improved. We conduct transfer matrix method (TMM) based simulations, considering a composite laminate to be an assemblage of anisotropic unidirectional fiber reinforced thin plies, with a view to assess the viability of these two strategies. Our results show that trying to enhance the longitudinal conductivity of the fibers is, by far, the more rewarding strategy. Finally, we conduct experiments on composites with carbon nanotubes dispersed in the epoxy matrix, and fibers with grafted nanotubes to reinforce the point. Using uni‐directional carbon fibers grafted with carbon nanotubes, the total shielding effectiveness in the direction perpendicular to the fibers increased from to and that along the fibers increased from to .