Clarifying the mechanisms of edge glow generation in CFRP laminates exposed to simulated lightning currents

Abstract

This study examines edge glow mechanisms of CFRP laminates exposed to simulated lightning current by performing direct electrical conduction tests. An impulse electric current, in accordance with SAE ARP 5412B, was applied to the laminates. Numerical simulations based on finite element analysis (FEA) were performed to clarify the voltage and temperature distributions of the CFRP laminates. The analytical results were validated using the experimentally obtained I–V characteristics and temperature responses. Resultingly, edge glow was observed in quasi-isotropic but not in unidirectional and cross-ply laminates. The edge glow was suppressed more in silicone oil than in air. When the edge glow did not occur, the numerical simulation results, I–V characteristics, and temperature response, exhibited good agreement with the experimentally obtained results. Contrary to Joule heating, potential differences of several hundred volts between each layer, which cause dielectric breakdown in the testing atmosphere, are the criterion for edge glow formation.