Algorithmic treatment of shells and free form-membranes in FSI

The aim of this contribution is to propose a methodology for the analysis and improvement of light, thin-walled structures with reference to aeroelastic effects. Those kind of problems demand for the appropriate combination of different physical and numerical disciplines to account for the relevant factors inherent to the simulation of light, thin-walled structures undergoing large displacements as well as highly turbulent air flows. To fulfill these requirements the occurring wind-structure interaction is accessed by a surface-coupled fluid-structure interaction (FSI) method. This is realized in a modular and flexible software environment with the use of a partitioned coupling approach: the structural field is solved by the in-house finite element program CARAT using several finite element types and advanced solution techniques for form finding, nonlinear and dynamical problems. The flow field is solved by the CFD software package CFX-5 of ANSYS Inc. A prerequisite to allow for the assessment of aeroelastic problems, beyond the mere exchange of data between the two physical fields, is the utilization of stable as well as efficient coupling strategies. In particular, it is shown that in the case of lightweight structures interacting with incompressible fluid flows the coupling strategy plays an important role regarding the feasibility of the simulations. This contribution will present theory and realization of a corresponding implementation enhanced by illustrative examples. Moreover, the comprehensiveness of this approach opens the possibility for multiphysics optimization.