AE Behavior of Lightning-Damaged CFRP during Compression-After-Impact Test

초록

Carbon-fiber reinforced plastics (CFRP’s) were made of nano-particles-coated carbon fibers and tested under compression-after-impact (CAI) mode, where the progress of further damage due to compressive loading has been monitored by acoustic emission (AE). The impact damage was induced not by mechanical loading but by a simulated lightning strike. Carbon prepregs prepared by coating of conductive nano-particles directly on the fibers and the CFRP coupons were subjected to simulated lightning strikes with a high voltage/current impulse of 10~40kA within a few microseconds. The effects of nano-particles coating and the degree of damage induced by the simulated lightning strikes on AE activities were examined, and the relationship between the compressive residual strength and AE behavior has been evaluated in terms of AE event counts and the onset of AE activity with the compressive loading. The degree of impact damage was also measured in terms of damage area by using ultrasonic C-scan images. From the results assessed during the CAI tests of damaged CFRP showed that AE monitoring appeared to be very useful to differentiate the degree of damage hence the mechanical integrity of composite structures damaged by lightning strikes.