ELECTRICAL CONDUCTIVITY MEASUREMENTS AND LIGHTNING STRIKE RESULTS OF NANO/MACROMATERIALS ENHANCED POLYMERIC COMPOSITES

摘要

Polymer matrix composites (PMCs) have been widely used in aerospace applications because they are lightweight. However, PMCs have poor electrical conductivity as opposed to metals; thus, significant damage to an aircraft may occur when it is struck by lightning. The research presented here was initiated to develop an electrically conductive multifunctional composite system that will experience minimal or no lightning strike damage. The nano-macromaterials evaluated for making conductive composites were nickel nanostrands (NiNS), single-walled carbon nanotube (SWCNT) buckypaper (BP) including random, aligned, and mixture of SWNT and vapor-grown carbon fiber (VGCF), copper mesh (Cu mesh), nickel-coated carbon fibers (NiCCF), nickel-coated carbon fiber nonwoven (NiCCF NonW), and PR-25 vapor-grown carbon fiber. These conductive materials were incorporated on the surface in reinforced AS4/Epon 862/W composites. The electrical conductivity measurements and lightning strike results of the conductive polymeric composites are presented. Addition of the random buckypaper to the Cu mesh did improve the electrical conductivity by 12% as compared to the composite containing only Cu mesh. However, the addition of random BP to the Cu mesh did not improve the lightning strike damage area under a Zone 2A (100 kA) lightning strike simulation test. The addition of the BP or addition of the PR-25 veil to the NiCCF led to electrical conductivity increases of up to four times that of the composite that contained NiCCF itself. The lightning strike data shows a 34-48% decrease in fiber damage or smaller damage area where the aligned BP and mix (SWNT+VGCF) BP was added to NiCCF. This approach for lightning strike protection of composites is very promising and lightweight. This research attempts to explore the relationship between volumetric electrical conductivity and lightning strike protection of composites for various systems.