Ground Vibration Test and Aeroelastic Analyses of the CIRA Unmanned Space Vehicle

This paper deals with the numerical and experimental activities performed by CIRA for the Aeroelastic flutter predictions and the numerical structural model validation of the CIRA Unmanned Space Vehicle in the first phase of the Dropped Transonic Test campaign. Starting from the FE model, the numerical results have been used in order to plan the test strategy and to find the optimal location for sensors and shakers, allowing the optimal control and observation of the structural modes in the frequency range of interest. A dedicated suspension system has been designed and realized in order to achieve the test article free free boundary conditions. The Ground Vibration test has been carried out in order to characterize the experimental dynamic model of the vehicle by using both the Phase Resonance (Normal Mode) and the Phase Separation techniques. A correlation analysis between the experimental modal data and the numerical results has been performed. The aeroelastic model has been updated on the basis of experimental FRFs and modal parameters, by minimizing the discrepancies between the FE model predictions and experimental data. Finally the validated numerical model has been used to investigate the aeroelastic phenomena. The interactions of elastic, inertial and aerodynamic forces have been predicted and the flutter speeds have been calculated.