Modeling the lightning continuing current electric arc discharge and material thermal damage: Effects of combinations of amplitude and duration

Abstract

The damage depth of a material is a key parameter for industrial objects in consideration of the lightning threat. The continuing current component in a multiple lightning sequence features a large charge transfer, which often leads to the dominant damage depth for electrically conductive materials. Laboratory simulation of the lightning continuing current is prone to misinterpretation due to various combinations of the current amplitude and duration in fulfillment of the fixed charge requirement of 200 C (±20%) in standards. This study employs a Unified Plasma-Material Finite Element Model (UPM-FEM) that is developed based on the classical magnetohydrodynamics method to analyze the influence of the current amplitude-duration combinations on the arc-material interactions. The energy originated from different physical processes, the heat flux and current density on material surface, and the material damage response are predicted using the UPM-FEM and compared for different amplitude-duration combinations at a fixed transfer charge. We report that the Joule heating, thermal conduction, radiative emission, and electronic enthalpic flux jointly determine the energy budget injected to materials at low current levels (≤300 A). While at higher currents (≥500 A), the thermal conduction contributes less significantly compared to the other energy items. The more pronounced increase of radiative emission heat loss will bring a saturation trend in arc properties and the material damage. A combination with a big current amplitude is recommended for achieving consistent arc properties and material damage in lightning continuing current test.