Understanding how arc attachment behaviour influences the prediction of composite specimen thermal loading during an artificial lightning strike test

High speed image analysis of experimental lightning strike testing on composite specimens has demonstrated complex time-dependent arc attachment behaviour. To date simulation studies of lightning strike direct effects on composite materials have overlooked or idealised the observed arc attachment behaviour. This is significant as these preceding studies have also demonstrated joule (resistive) heating is a major contributor to composite material damage and thus the application of the current load is critically important. The objective of this paper is to quantify how arc attachment behaviour influences the prediction of composite specimen thermal loading during a simulated lightning strike test. This is achieved through a simulation study modelling experimental arc attachment behaviours referenced in the literature. The simulation results are compared with measured test specimen damage. The results quantify for the first time the significance of arc attachment behaviour, demonstrating how realistic representation of arc expansion and arc movement can alter the predicted thermal loading and generate thermal damage patterns comparable to measured experimental damage.