Effect of lightning arc on damage characteristics of carbon fiber-reinforced polymer composites with a fastener by an improved calculation method

This study investigates the lightning damage characteristics to carbon fiber-reinforced polymer (CFRP) composites with a fastener under the long-term lightning components B + C, focusing on the damage mechanisms influenced by the lightning arc channel. The lightning arc simulation model of specimen is constructed, the current density and heat flux distributions of the specimen are obtained.Using the arc model,a thermal-electrical-structural coupling model is proposed, enabling an analysis of the interaction between the specimen and lightning channel. Results indicate that arc heat in the lightning channel is the primary cause of specimen damage. The damage decreases in the thickness direction, forming a ‘funnel-shaped’ damage pattern with a wide upper part and a narrow lower part. The simulation indicates that damage area under the arc heat effect is 24 % smaller than the experimentally observed damage area, while damage under Joule heat is 97 % smaller. Compared with the unprotected specimen, the damage area of the copper mesh-protected specimen is 54 % smaller; however, the damage area is more concentrated and intense. Therefore, relying on a single component current waveform to assess protective effectiveness is insufficient. This study provides a reliable basis for analysing the lightning protection designs for CFRP composites in lightning environment.