Lightning Strike Protection and EMI Shielding of Fiber Reinforced Composite Using Gold and Silver Nanofilms

Abstract

Carbon fiber reinforced composites are very much imperative to future-generation aircraft structures. However, lightning strike protection (LSP) and electromagnetic interference (EMI) are main concerns. Carbon fibers have very good mechanical properties with the best strength-to-weight ratio, but they are very poor conductors of electricity. These fibers must be reinvented to increase the surface conductance to provide high electrical conductivity to the aircraft structure. The present study deals with preparing composite sandwich structures of carbon fibers used for commercial nacelle applications subject to lightning strike effects with different metallic nanofilm of gold (Au) and silver (Ag) measuring approximately 100 nm. These metallic nanofibers were co-cured on the top layers of composite panels during vacuum curing process. In our laboratory, lightning strike results for a composite sandwich structure using nanofilms were obtained to observe lightning strike damage and structural tolerance necessary to observe the damage tolerance capability. Resistance of composite panels with metallic nanofilm under various strains was studied. It was found that resistance of the metallic nanofilm increased under strain. The voltage was found to be low; hence, an increase in current would help to reduce the damage on composite panels due to lightning strikes, and the same theory would be applicable to EMI. No EMI was absorbed or reflected in the nanofilm using the P-static test. When lightning strikes were applied to composite coupons, the resulting damage from the currents was reduced on those with metallic nanofilms.