From the Sky to Orbit: The Crucial Role of FEM Simulations in Aerospace
FEM simulations in aerospace serve one purpose: knowing how a structure will behave before it is built. In this article we explain why they have become essential and how we use them in our programmes.
In the aerospace sector, the margin for error is zero. Whether it’s certifying a crashworthy helicopter seat or calculating the deformation of a satellite subjected to the thermal shocks of Earth’s orbit, modern engineering cannot do without advanced numerical simulations.
At SIM4FLIGHT, we use Finite Element Method (FEM) analysis to predict the behavior of structures before they are even manufactured. Using software such as Hypermesh, Optistruct, and MSC Nastran, we create numerical models on which we perform static, fatigue, and thermoelastic analyses.
This approach allows us to optimize component weight (crucial in aeronautics and space), reduce physical prototyping costs, and ensure that every structure passes the strictest qualification and certification processes, as demonstrated by our recent work on the AW09 and OHB Genesis programs.
How FEM simulations in aerospace work
The finite element method divides a structure into thousands of small elements, connected at their nodes. Then the solver works out the equations of elasticity for each element. So it rebuilds the displacements, strains and stresses of the whole part. The output is a colour map that shows where the material works hardest.
However, the value is not in the map but in the choices behind it. You have to decide how fine the mesh should be and how to represent bolts and rivets. You also choose which boundary conditions and loads to apply. For this reason, a good model always comes from a dialogue between the analyst and the people who know the part.
Global model and detailed model
In aircraft programmes we usually work on two levels. First, we build a global model with relatively large elements. It describes how loads travel through the structure. Then we extract the forces in critical areas and build a detailed model with a fine mesh. This lets us read stresses accurately around holes, fillets and attachments.
This way you get the best of both. The global model stays light and is easy to update, while the detailed one gives the numbers for margins of safety. On the Leonardo AW09 programme, for example, we used exactly this approach for stress recovery at Limit Load.
Fatigue and thermoelastic loads
An aircraft structure rarely fails because of a single overload. Much more often it fails through fatigue, after millions of cycles. To assess it we define the Transfer Function, that is the link between external loads and the stress at a critical point. Once we calculate it on the FEM model, we can estimate fatigue life over thousands of flight conditions.
In space, instead, the main problem is heat. A satellite in orbit moves from sunlight to the Earth’s shadow several times a day, and temperature swings distort the structure. With thermoelastic analyses, like those for the OHB Genesis satellite, we calculate these distortions. Then we check that instruments and panels stay aligned.
Why FEM simulations in aerospace do not replace testing
Simulations do not remove the need for tests, but they make tests more targeted. Thanks to the model, we already know which parts are critical, where to place strain gauges and which values to expect. In addition, when the test confirms the analysis, the correlated model becomes a reliable tool for future changes too.
In short, simulating before building means less weight, fewer prototypes and fewer surprises during qualification. If you have a component to verify, look at our numerical simulation services or write to us from the contact page: an engineer will answer you directly.