Test on damage and mechanical property degradation of composite laminate with fastener subjected to lightning strike

Artificial lightning strike testing was performed on a series of carbon woven fabric/epoxy laminate with metal fastener, and damage was assessed using visual inspection, ultrasonic testing, micro X-ray inspection and high-power microscope to analyze the damage mode, damage mechanism and damage characteristic of composite laminate with metal fastener under lightning current direct effect, meanwhile, mechanical property degradation extent of composite laminate with metal fastener was also assessed using material mechanical property test system. Research results indicate that due to the lightning current distributing effect aroused by mental fastener, delamination is the mainly damage mode of composite laminate with metal fastener when subjected to lightning strike, and it is distributed along the whole thickness direction of laminate. There is a lightning current intensity threshold about whether composite laminate with metal fastener occurs lightning strike damage, and when the lightning current intensity is lower than it, composite laminate with metal fastener will not appear lightning strike damage. During the process of static tension, because lightning strike damage around fastener hole will arouse the effect of stress distribution, the tensile loading capacity of composite laminate with metal fastener with lightning strike damage increases first and then decreases with the increasing lightning peak current.