Electrical and thermal behaviour of Z-pin reinforced carbon-fibre composite laminates under fault currents

Carbon-fibre reinforced polymer (CFRP) composites typically have poor electrical conductivity, primarily due to the conductive carbon fibres being separated by the insulating polymer matrix material. This is even more so in the case of interlayer toughened material systems that have an increased interlaminar spacing between the conductive carbon fibre layers. To mitigate the poor electrical conductivity of CFRP composites, the behaviour of Z-pinned laminates under electrical current was here studied experimentally. The in-plane and through-thickness fault currents were investigated for a quasi-isotropic (QI) composite laminate made from M21/IMA prepreg. Two kinds of pin materials (T300/BMI composite and copper) were used at two different volume fractions (0.1 % and 0.25 %). The pins reduced the through-thickness current resistance by two orders of magnitude, with a much smaller data variation, and up to one order for the in-plane direction. Through the use of electrically insulated pins, it was found that the electrical conductivity enhancement is caused by the fibre crimping around the pin and is unrelated to the pin material. Z-pins decreased the temperature increment caused by Joule heating during fault currents, thereby ensuring structural safety.