Modelling and understanding edge glow effects on material failure resulting from artificial lightning strike

This paper examines the influence of edge glow effects (arcing of current from specimen side surfaces) on the prediction of material failure during an artificial lightning strike. A novel modelling approach is proposed to incorporate edge glow effects. Finite Element simulations are undertaken to examine modelling strategies and results compared against experimental data. Simulations also examine the influence of inter-ply properties, as together with edge glow modelling, these may be expected to impact the predicted current path through a test specimen. Unprotected carbon fibre / epoxy composite material and Society of Automotive Engineers (SAE) lightning test Waveform A are studied. Inter-ply thermal and electrical conductivities are modified either wholly or partly (by 50% or 100%) from a reference magnitude. Results reveal that changes to inter-ply contact can affect the damage area and depth predictions, varying damage area predictions up to 22%. However, it is shown that edge glow effects produce an even more significant change in the prediction of thermal damage behaviour, reducing predicted damage areas, by up to 55%, and increasing damage depth by 14%.