Lightning strike damage test research for carbon fiber/epoxy resin matrix composite laminates when subjected to combined lightning current waveforms

In order to evaluate the lighting strike damage degree and characteristics of the carbon fiber/epoxy resin matrix composite material under different aircraft lighting strike zones, three different lighting current combined waveforms (A+B, D+B+C and A+B+C+D) were used to simulate lighting strike experimental research on two kinds of composite specimens with different sizes(Type1 and Type2).Damage was assessed using visual inspection and ultrasonic testing to analyze and evaluate the lighting strike damage degree and characteristics of the composite material on the plane 1A, 2A and 1B lighting zone. Meanwhile, the damage resistance characteristics of the carbon fiber/epoxy resin matrix composite specimens with copper wire mesh were compared to the benchmark values of unprotected specimens under different lighting strike zones. The results show that under different lighting strike zones, the damage modes of the carbon fiber/epoxy resin matrix composite materials caused by lighting current are basically the same, including fiber fracture, matrix ablation and delamination. For the same type of test specimens, most severe lighting damage is in the 1B lighting zone followed by 2A lighting zone, and 1A lighting zone has the least degree of damage. Type1 test specimens with small length-width radio have the less damage degree than the ones with large length-width radio under the same lighting strike zones. 0.25 mm copper wire mesh can effectively protect the carbon fiber/epoxy resin matrix composite material. Type2 protected test specimens have 88.9%, 53.9% and 68.7% damage degree compared to the unprotected ones, which are located in 1A, 2A and 1B lighting zones.