Understanding the impact of standardized SAE waveform parameter variation on artificial lightning plasma, specimen loading and composite material damage

Previous works have established strategies to model artificial test lightning plasma with specific waveform parameters and use the predicted plasma behavior to estimate test specimen damage. To date no computational works have quantified the influence of varying the waveform parameters on the predicted plasma behavior and resulting specimen damage. Herein test standard Waveform B has been modelled and the waveform parameters of ‘waveform peak’, ‘rise time’ and ‘time to reach the post-peak value’ have been varied. The plasma and specimen behaviors have been modelled using the Finite Element (FE) method (a Magnetohydrodynamic FE multiphysics model for the plasma, a FE thermal-electric model for the specimen). For the test arrangements modelled herein it has been found that ‘peak current’ is the key parameter influencing plasma properties and specimen damage. A 10% increase in peak current magnitude (and resulting 21% increase in action integral) results in a 12% increase in plasma peak pressure, a 5% increase in specimen surface current density, and subsequently a 8.7% increase in thermal damage volume and a 15.2% increase in thermal damage depth. Overall action integral has the strongest correlation with four of the five considered damage measures. Peak current has the strongest correlation with the other damage measure.