Validation of Structural Modeling for Realistic Wing Topologies Involved in FSI Analyses: RIBES Test Case

The procedures that couple finite-element method (FEM) solutions and fluid dynamic solvers to develop so-called high-fidelity fluid-structure interaction (FSI) numerical methods involve a series of awkward processes that affect both the robustness and accuracy of the tools. In particular, two aspects represent critical issues when coupling the two environments in two-way analysis procedures: the mapping of the computational fluid dynamics (CFD) solution, in the form of loads, to the structural model, and the adaptation of the CFD domain according to the shape deformation estimated by the FEM analysis. The enhancement of such coupling, and, more generally, the improvement of accuracy in numerical FSI procedures, was the objective of the European Union (EU)-funded radial basis functions at fluid interface boundaries to envelope flow results for advanced structural analysis (RIBES) research project. Specifically, the main tasks involved the development of a mapping procedure capable of nullifying the interpolation errors in the mapping process and the generation of an experimental database aimed at the validation of FSI methodologies while focusing on the structural modeling of realistic aeronautical topologies. The problem of the solver coupling was solved by approaching the CFD domain adaptation problem using a mesh morphing technique based on radial basis functions. The tool can smoothly propagate the deformation of wet surfaces by directly importing the vector displacements of the FEM mesh nodes in the native format of the structural solver. In addition to computational fluid dynamics-computational structural mechanics (CSM) direct coupling, a modal approach to model the FSI mechanism is proposed and was compared with the two-way procedure. This paper reports the validation of the two aeroelastic analysis methodologies performed within the RIBES project. The wind tunnel campaign investigated the structural aeroelastic response of realistic wing structures. The validation verified the tool's capability to capture the stress state and the deformation of a typical wing box structure under aerodynamic loads. (C) 2020 American Society of Civil Engineers