Damage Mechanism of Carbon Fiber Composites with Fastener after Lightning Strike

Carbon fiber composites (CFRP) are widely used in aircraft fuselage and wing components, and fasteners are widely used in aircraft mechanical connections, therefore, it is necessary to conduct research on the lightning damage characteristics of carbon fiber composites with fastener. In this paper, the difference in surface damage of CFRP with and without fasteners under different lightning current peaks was studied. The linear damage of CFRP surface was observed with 3D laser microscope. The test results show that the damage degree of CFRP with fastener along the carbon fiber direction is less when the lightning current peak value is small, while the damage degree of CFRP with fastener along the carbon fiber direction increases rapidly with the increase of lightning current peak value, which exceeds the damage degree of CFRP without fastener. CFRP without fasteners show linear damage in the direction perpendicular to the carbon fiber, while the linear damage of CFRP with fasteners is not obvious. Through the 3D laser microscope observation, the linear damage part of carbon fiber appears obvious fracture.