Improved electrical conductivity of NCF-reinforced CFRP for higher damage resistance to lightning strike

Silver-coated knitting yarns are used in an NCF to increase the electrical conductivity of CFRP-laminates. A test textile containing section-wise four different knitting yarns has been produced. The threads differ in yarn count and degree of silver-coating. Depending on the yarn's linear resistance, the conductivity in thickness direction increases by up to two orders of magnitude to >100 S/m. The in-plane conductivity is significantly higher as well. Combining conductive knitting yarns with conductive toughening interleaves further increases the electrical conductivity. Lightning strike resistance benefits from the conductivity improvement. The damage decreases particularly in the lower fibre layers, e.g. at a depth of 1.0 mm by app. 90%. In spite of the higher laminate conductivity, additional conductive interleaves do not further improve lightning strike resistance. The damage is smaller than in the reference, but larger than in a comparative laminate where only the knitting yarn is conductive.