Development of equivalent model of external fuel tank assembly for dynamic characteristics analysis of aircraft

Aircraft are frequently equipped with various external stores for mission performance. Because these external stores may cause structural instability of the aircraft, an evaluation of the interactions between the aircraft and the external stores is required. For this purpose, an analysis of the characteristics of the aircraft dynamics reflecting an external store was performed. The finite element model used for the analysis of these characteristics should be able to simulate the dynamic characteristics of the component as accurately as possible, while using a minimum of nodes and elements. In this study, an equivalent model for dynamic characteristics analysis of an external fuel tank and installation pylon was constructed using MSC Patran/Nastran. The validity of an equivalent model of each component was confirmed by comparison with the modes of the full-scale model. Then, each component was assembled with connecting member and the modal analysis of the equivalent model assembly was performed to verify that the basic modes required for the analysis of aircraft dynamic characteristics can be well extracted. Finally, it was confirmed that the newly developed equivalent model assembly could be used for aircraft dynamics characteristics analysis through the equilibrium check by comparing to the modes of the full-scale model.