Modelling of aircraft skins

Computational electromagnetics is playing increasingly important roles in aircraft design and airworthiness clearance. These roles involve low frequencies for lightning, through HF, VHF/UHF and microwave for high intensity radiated fields (HIRF). In order to achieve the data required, which is generally currents and voltages on cables, it is clearly necessary to take full account of structural materials and their effects on electromagnetic fields. Indeed, for directly injected threats such as lightning, the structure plays a primary role in defining external as well as internal fields. The materials and their models fall into three categories: metals, composites of relatively poor conductivity, and dielectrics which may include some “loss” component. The methods for modelling the effects of these materials will be briefly described and their effectiveness, including the problems and limitations discussed. Since we almost exclusively use finite-difference time-domain and the related transmission line method, discussion will be confined the treatment of materials within these solution approaches