Lightning strike damage on the composite laminates with carbon nanotube films: Protection effect and damage mechanism

Carbon nanotubes can be used to protect composites from lightning strike due to their high electrical conductivity. A kind of carbon nanotube film was developed to protect composite structures here. Its lightning strike protection effect was studied. Artificial lightning strike tests were conducted on carbon nanotube film protected specimen, traditional surface silver coating protected specimen and pristine specimen in this paper. Coupled thermal-electrical finite element models were established to study the lightning strike protection effect and damage mechanism of two kinds of methods. Numerical results agree well with experimental ones, illustrating the validity of the models. The results show that lightning strike damage in the carbon nanotube film protected laminate is restricted in 5 composite piles and 5 carbon nanotube films close to the lightning strike surface. Whereas lightning strike damage in surface silver coating protected specimen is restricted in coating and 2 composite piles close to the lightning strike surface. Compared with the pristine laminate, damage in the laminate with carbon nanotube films decreases by 77.6% and 68.0% in area and depth respectively, whereas damage in the laminate with surface silver coating decreases by 66.1% and 92.0% correspondingly. The inserted carbon nanotube films can increase the electrical conductivity and conduct the strike current and energy along both depth and in-plane directions quickly, while surface silver coating mainly conducts the energy along in-plane direction.