Effect of Lightning Strike on the Compressive Strength of Carbon Fiber Reinforced Polymers—A Finite Element Study

Abstract

The use of polymer composites as structural materials has increased drastically in the recent past. While they possess qualities like high strength to weight ratio and corrosion resistance, the poor electrical and thermal properties make them vulnerable to damage due to lightning strikes. When struck by lightning, the electrical current takes more time to travel through polymers (matrix) as they are poor electrical conductors and causes heating near the strike area (resistive heating). The temperature gradient created by resistive heating leads to a change in material properties and results in the stiffness reduction of the structure. The carbon fiber reinforced polymers (CFRP), a widely used material in aircraft and wind turbine industries is weak in compression. Under pure compressive loading, the fiber-reinforced polymers (FRP) undergo localized buckling (kinking), due to the fiber misalignment (waviness) introduced during manufacturing. Kinking is identified as one of the failure modes in FRPs. After the lightning strike, kinking in FRP would be accelerated as the resistive heat generated causes thermal strains in addition to mechanical strains in the polymer matrix. This in turn leads to a drastic reduction in the compressive strength of the material. In the current study, a finite element (FE) analysis was conducted to obtain the compressive response of CFRP subjected to different current intensities using the commercial software ABAQUS.