Lightning Simulation Validation
EMA recently supported Bombardier in lightning simulation validation exercises for lightning effects on a full CSeries aircraft wing as well as a representative wing test box. The results were presented as two separate papers at the 2015 International Conference on Lightning and Static Electricity (ICOLSE) in Toulouse, France.
The two papers describe two validation campaigns in pursuit of 25.981 fuel system ignition FAA certification:
- A full scale aircraft with lightning injection in the wing
- An aircraft wing test box injected with full-scale lightning current
The purpose of the two tests was to validate a computational electromagnetic (CEM) model by a comparison with laboratory lightning testing. EMA3D with integrated MHARNESS version 4 was the CEM code under evaluation.
In summary, the EMA simulation correlated extremely well with the test results. An example of the correlation is shown in the figure below:
14 CFR 25.981(a)(3) and AWM 525.981(a)(3) require that design features in the aircraft fuel tank shall prevent ignition due to high currents and voltages that can result in sparking. It is essential to establish the aircraft lightning environment (threat levels) within the fuel tank structure to show it will not be of sufficient amplitude to cause ignition. Threat level definitions can be supported by simulation and analysis.
Simulation tools provide more extensive means to rationalize threat level predictions than by using development testing alone. Simulations also provide more extensive means to evaluate specific design features.
The two presentations for the full scale aircraft lightning testing campaign and an aircraft wing test box are embedded below. The published papers are available for the full scale aircraft lightning testing here and for the aircraft test box here.