Aero-elastic tool implemented in a preliminary aircraft design program suite

The objective of this project was to build a versatile static aeroelastic tool that can be easily integrated into the software suite CEASIOMpy used for preliminary aircraft design. To meet this objective the partitioned loosely coupled approach is used, which means that separated solvers are used to solve the aerodynamics and the structural mechanics parts of the problem. However, this approach leads to the the problem of mismatched meshes. This problem has been solved during this master thesis by building the solver Aeroframe 2.0 that is based on the theory of virtual work.

The aeroelastic (also called Fluid Structure Interaction (FSI)) simulations were made using state of the art validated solvers for both the fluid and the structure problem. The computational fluid dynamics (CFD) solvers used are the well known high fidelity SU2 solver and the vortex lattice method (VLM) solver PyTornado. Concerning the low fidelity three dimensional beam model, the finite element solver FramAT was chosen.

Aeroframe 2.0 is part of a software suite, developed in the framework of the European project AG-ILE 4.0. AGILE regrouping many aeronautics actors that are using each other strengths to push science forward. Working with many actors opened the opportunity to use an external structural finite element solver. This led to a function into Aeroframe 2.0 capable of linking input files generated from a NASTRAN solver used by DLR, which is one of the actors of the AGILE 4.0 project.

Coupling two CFD solvers and two finite element structural solvers, all having different mesh types, led to a complicated task. The SU2 solver works with a three dimensional grid, PyTornado with a surface of panels, FramAT uses three dimensional beam elements, and finally the external solver uses three dimensional structural elements. As mentioned above, to overcome this challenge the principle of virtual work was used.

Finally the first steps towards validation were made. Comparison of the results obtained from the analytical solution for a straight wing and the solution obtained by Aeroframe 2.0 was done. Both SU2 and PyTornado gave satisfactory results with the finite element solver FramAT. No validation was made for the combination of SU2 with the external solver and PyTornado with the external solver. Only functionality tests were made and are not presented in this report.