Mechanical and thermal contributions to the damage suffered by an aeronautical structure subjected to an intense and sudden electrical discharge
Résumé
Lightweight aeronautical structures and power generation structures such as wind turbines are fitted with protection systems designed and certified to withstand severe climatic events such as lightning strikes. During these events, high currents flow through the protection, but are likely to induce effects in the depth of the supporting composite structure and reach or even perforate pressurised tanks. By studying the damage suffered by a structure with different levels of protection, one could predict the damage that could occur in unprotected areas in the event of a partial discharge from power supply cables of future-generation aircraft or power station equipment. However, analysing the damage while the current is being delivered is very difficult and necessarily indirect via remote observations. In order to gain a better understanding of the contribution of mechanical and thermal loading resulting from the electrical source of a high current delivered in a few microseconds, by analysing similarities in the damage generated by a lightning, we carried out test campaigns and simulated laser shocks (mechanical) and electron beam shocks (thermomechanical) and compared them with lightning strike damage. The instrumented experimental environment that has been set up will be used to analyse the sources of damage that can be observed on the digital twin of these experiments. The results presented here are experimental results and corresponding simulations (digital twin) of laser impact tests on composite aeronautical laminates with or without lightning strike protection. The use of numerical simulation makes it possible to validate some hypotheses about the damage behaviour of the CFRP composite laminates tested, compared with traditional quasi-static characterisations. Through comparisons with experiments, the simulation also enables to determine dynamic interface failure thresholds and the tracing of the mechanical contribution of a lightning strike or high current discharge.