Ground flutter simulation test (GFST) is a semi-physical test technique that determines the flutter characteristics of the aircraft on the ground without a wind tunnel. The distributed unsteady aerodynamics is simulated by several electrodynamic shakers in real-time. A new method of aero-dynamic model reduction based on generalized aerodynamic forces is proposed. Firstly, the gener-alized aerodynamic force matrixes in modal space are transformed to aerodynamic influence ma-trixes in physical space. Then, the distributed unsteady aerodynamic forces, which originally ex-erted on all nodes of the structural finite element model, are concentrated equivalently to several exciting points by surface spline method. Thus, we obtain the frequency domain reduced-order aerodynamic model. Finally, the reduced-order aerodynamic model is converted from frequency domain to time domain via minimum-state method. Simulation results show that the proposed method improves the accuracy of the reduced-order aerodynamic model compared with the previous method. Moreover, the presented method decreases the number of exciting points on the structure, so reduces the difficulty of performing the ground flutter simulation test.
