ONERA has world-renowned expertise in lightning strikes and their consequences, built up over the course of 40 years of laboratory and flight experience, theoretical developments, and exchanges with aircraft manufacturers and operators. These skills are also used in developing lightning protection systems for critical infrastructures.
Protecting critical infrastructures
In June 2021, ONERA carried out an electromagnetic measurement campaign on the CEA Cadarache's Jules Horowitz nuclear reactor site. The aim was to analyse the electromagnetic behaviour of the buildings and components constituting the lightning protection system, in particular by carrying out local injections of low-level current. Deploying the instrumentation on a building of this size required the development of specific electromagnetic field sensors, remote digitisation instruments, and an acquisition software GUI based on the buildings’ CAD.
ONERA uses numerical simulation / experimental dialogue, conducting “full-scale” tests in order to recalibrate with respect to complex physics, then to develop ever more accurate and reliable models. Once post-processed, these measurements can be used to construct a digital model of the site in order to assess via numerical simulation the residual stresses on the buildings in the event of an actual lightning strike.
ONERA: the lightning specialist for launch vehicles
ONERA specialists in electromagnetic compatibility have contributed to the definition and optimisation of the lightning protection system at the launch sites for Ariane, Soyuz and Vega launch vehicles. Using their models, they have been able to numerically simulate the magnetic fields and currents following a lightning strike on one of the four interconnected masts protecting the launch tower.
Aircraft safety is a must
ONERA is at the front line, shoulder to shoulder with the industry, in analysing the physical phenomena at play, through highly instrumented experiments, then simulating them through calculation. The scientists generate lightning in silico (by computer simulation) and observe the virtual damage.
This is particularly necessary since, unlike metal aircraft, which are naturally protected against lightning, this is not the case with composite structures, which are increasingly used today to reduce aircraft weight. It is therefore necessary to understand the mechanisms of lightning strikes on these materials, and ONERA provides manufacturers with the tools necessary to design stronger structures and incorporate protections. These direct effects also affect equipment (antennas, sensors, de-icing systems, engines, etc.) installed on the skin of the aircraft. The aircraft’s internal systems (electrical and hydraulic networks, avionics, tanks, etc.) will also be protected against the indirect effects of lightning and electromagnetic emissions.