Study on the Factors Influencing the Damage Modes of Carbon Fiber-Reinforced Polymer Composites with a Fastener Under Lightning Strike Conditions

The direct effects of carbon fiber-reinforced polymer (CFRP) composites with a fastener in lightning environments are very complicated. Experimental models were designed to understand the influence of different factors on the damage modes. First, different specimen structures, including unidirectional and woven fabric, were studied. Second, the damage characteristics of the two cases where current injection occurred in the fastener part and the carbon fiber part were experimentally studied. Finally, the different grounding points were studied. The experimental results showed that the woven fabric structure can conduct current better, and the area of lightning damage is smaller than that of the unidirectional ply. The lightning experimental conditions had a significant influence on outgassing, delamination damage characteristics and the lightning phenomenon. A high-speed camera was used to observe the lightning action process. The mechanism of electrical and thermal conversion between fastener and CFRP composites was revealed by discussing the lightning strike process. The damage morphology and lightning phenomena caused by an instantaneous electric field distortion distribution was deduced. The current work provides a reference for effectively designing lightning protection strategies under different lightning strike conditions.