Artificial Lightning Tests on Metal and CFRP Automotive Bodies: A Comparative Study

Carbon fiber reinforced plastic (CFRP) has been used in automobiles as well as airplanes. Because of its light weight and high strength, CFRP is a good choice for making vehicle bodies lighter, which would improve fuel economy. Conventional metal bodies provide a convenient body return for electric wiring and offer good shielding against electromagnetic fields. Although CFRP is a conductor, its conductivity is much lower than that of metals. Therefore, CFRP bodies are usually not useful for electric wiring. In thunderstorms, an automotive body is considered to be a Faraday cage that protects the vehicle’s occupants from the potential harms of lightning. Before CFRP becomes widely applied to automotive bodies, its electric and electromagnetic properties need to be investigated in order to determine whether it also works as a Faraday cage against lightning. In this article, CFRP and metal body vehicles were tested under artificial lightning. The electric discharging caused by the artificial lightning in the vehicles was investigated under different grounding conditions. A CFRP roof plate and a CFRP box mimicking vehicle cabin were also examined with artificial lightning to study generic cases, which did not depend on vehicle body shapes. The comparative study showed no significant difference between the CFRP and metal vehicles in lighting-strike performance.