Finite Element Modeling and Updating of a Supersonic Jet using Ground Vibration Testing data

A comprehensive Finite Element Model (FEM) of the F-16 Fighting Falcon is developed, emphasizing the inclusion of the fuselage and empennage in response to Ground Vibration Test (GVT) data. The GVT, which provides the first in-depth insight into an aircraft's dynamic behavior, is instrumental in validating and refining the FEM created during the development phase. Post-GVT, the model’s eigenfrequencies and mode shapes are analyzed, and the FE model is iteratively updated to ensure it accurately represents the dynamic characteristics of the test aircraft. Unlike previous studies that primarily focused on the aircraft's wings, this work extends the FEM to encompass the entire structure, utilizing data from all accelerometers positioned during the physical test. By doing so, it captures the degrees of freedom associated with each sensor, creating a full-scale representation of the F-16’s structural response under testing conditions. A crucial aspect of this research involves the integration of nonlinear elements in the FEM, specifically addressing the nonlinearities stemming from the interface between the dummy payload and its support structure. By applying a model updating process that incorporates these nonlinear interactions, the FEM is iteratively refined until the discrepancies between the analytical model and experimental data are minimized, ideally converging towards zero error. This refined, nonlinear FEM model offers a more precise representation of the F-16’s dynamic response, making it a robust tool for advanced analyses, including global structural assessments and flutter predictions. This study ultimately contributes to enhancing the fidelity of FE models in the aircraft design and certification processes, ensuring a high level of accuracy that aligns closely with real-world behavior.