Lightning strike simulation can be performed on large scale aircraft, or on smaller boxes in accordance with DO-160. The purpose of simulating a lightning strike is to look on the coupling effects on fuel lines, buss bars, and cable bundles. Simulated results often drive material changes early on before problems arise. As materials move away from aluminum to composites, it becomes more and more difficult to protect large systems from lightning strikes.

Let's walk through a very general high level simulation on an Airbus A380

To begin a CAD model of the aircraft is imported. Material properties are then assigned to individual components to represent their structure. Multilayer hybrid composites can be created to investigate current flow through composite skins.

While there are several types of lightning, the type that concerns us is cloud to ground lightning. The RTCA DO-160 test uses five different waveforms to represent lightning. In the simplest case, the most popular waveform used to simulate a lightning surge is the ANSI/IEEE C62.41 combination wave. Typically Component A, a high-current pulse characterized by the custom waveform shown above is simulated as it poses the greatest threat. It is a direct current transient that has been recorded to reach up to 260,000 amperes and last for a duration of up to 200 microseconds. Typical rate of current rise with respect to time is 3 X 10^10 A/s, but could reach 2 X 10^11 A/s. On the average, it will reach 20,000 amperes for a 50 microsecond duration. Strikes above 200,000 amperes are considered rare.

Since we simulate using the Finite Integration Technique, results can be had same day on a state of the art PC. Typical structures will have known attach and detach points, which can be used as points of reference for current entering and exiting the structure. In the above figure, a nose to wing strike is simulated where the current enters Port1 and excites Port2. While the engines are closer to the ground, field enhancement around the sharp wingtips makes more likely to be an attach/detach point. Current flow can be analyzed as a function of time. In the example above, the current density is animated from t=0 to t=30ns.

Results can be viewed in many forms, and can be presented to the customer in ways to effectively communicate the results. Give us a call and let us quickly validate your design, or recommend design changes.