Dynamic characteristics of carbon fiber reinforced polymer under nondestructive lightning current

Abstract

An experiment platform was established to study the measuring methods for the dynamic impedance characteristics of carbon fiber reinforced polymer (CFRP) under nondestructive lightning component A. On basis of the experimental results, the two‐electrode testing system was conducted and silicone grease was coated between the electrode and specimens to reduce the high‐frequency discharging disturbances. The dynamic characteristics of CFRP under lightning current (the peak time TP is 30.2 μs and the duration time Td is 72.2 μs) were investigated by measuring the voltage between two terminals of specimens and the impulse current flowing through the tested CFRP in this article. The experimental results show that the CFRP has a strong conduction capability under the lightning impulse, and its dynamic resistance has significant nonlinear characteristics which decrease from 20 Ω to 2 Ω with the impulse current increasing from 5 A to 100 A. The peak time of voltage is little prior to that of the impulse current, which showed inductive effect. Moreover, the residual voltage may maintain a positive or negative value within a certain time after the lightning current returning to zero, which called the voltage holding effect. The experimental phenomena such as inductive effect, nonlinear behavior, and voltage‐holding effect can be explained by the proposed conduction model of CFRP qualitatively, in which the internal layer‐structures and the conductivity of CFRP are considered comprehensively. This work will provide a theoretical support for further researches of electric characteristics, thermal degradation of CFRP, and also lays a foundation for its widely applications in aerospace industries. POLYM. COMPOS., 39:1514–1521, 2018. © 2016 Society of Plastics Engineers