Frequency Domain Analysis for the Prediction of Lightning Indirect Effects and Comparison to Measured Data from Two Composite Test Articles

A lightning indirect effects analysis of a conductor over graphite composite structure was performed using a frequency domain analysis. An internal Boeing analysis code, EM_Model, was used to predict and model test data from two graphite composite test articles. The first was a simple graphite panel with an aluminum tube placed at various heights above the panel. The aluminum tube is representative of either hydraulic or fuel lines, or cable bundle shields. The second test article was the outboard section of a graphite wing-box with two aluminum tubes internal to the structure. A series of access panels in the wing skin provided a source of aperture coupling in addition to the diffusion currents. Both tests made low level CW (LLCW) measurements of the tube transfer function and were compared to model results with good agreement.