Application of the Finite Difference Time Domain Code EMA3D to the Modeling of Indirect Lightning Effects in a Composite Panel and Wing Box

The Finite Difference Time Domain (FDTD) method (as implemented in the commercial software package EMA3D) is used to model indirect lightning effects in a composite three bladed panel and a composite wing-box. The analysis is compared with low level continuous wave (LLCW) tests performed in the Boeing Lightning Effects Laboratory. Measured data include transfer functions for currents induced on metal tubing interior to the three-bladed-panel and wing-box. The thin wire and thin plate formalisms provided in EMA3D are used to model the composite surfaces and metallic conductors such as pipes in the wing-box. The wing-box is simulated both with and without apertures. The modeling results showed excellent agreement with measurements over a broad frequency range demonstrating the usefulness of FDTD as a predictive tool for lightning frequencies.