Ablation damage assessment of aircraft carbon fiber/epoxy composite and its protection structures suffered from lightning strike

Aircraft carbon fiber/epoxy composite material is sensitive to lightning strike. Its damage assessment and protection design suffered from lightning strike is becoming increasingly important. Four different types of carbon fiber/epoxy composite laminates are selected, which are without protection, with full spraying aluminum coating, with local spraying aluminum coating and with spraying aluminum coating on glass cloth pasted to fastener head, respectively. Impulse electrical current tests were performed by implementing electrical current waveforms with different peak values with regard to different lightning zonings. Three-dimensional finite element models of composite laminate and its protection structures are accurately built to assess lightning ablation characteristics based on the coupled thermal/electrical/structural analysis and element deletion method, in which different electrical and thermal physical properties of the elements are defined depending on different temperature conditions. The results show that simulation results are good agreement with experimental results. Fiber damaged area, the damaged area and the maximum damaged thickness increases with the increase of electrical current peak. Aluminum coating has a good effect on anti-lightning strike. The thicker aluminum layer and the better to anti-lightning strike.