On Mechanism of Aerodynamically Coupling Flutter for Two-Degree-of-Freedom Plate Section

Since the coupling flutter of bridge decks is a vibration phenomenon between the single degree-of freedom(DOF) flutter and the coupling flutter of thin plate,it is helpful to study the flutter mechanism of an idealized plate section.A 2DOF coupling flutter analysis was derived from the torsional and vertical coupled motion equations of system,in which the frequencies and damping ratios of the system vibration characteristics were expressed implicitly as functions of flutter derivatives.The comparison of the presented results with the exact ones by a characteristic analysis of system motion equations was performed and the presented method was proved reliable in its methodology and proper in its application.Moreover,the mechanism of aerodynamically coupling flutter for an idealized plate section was investigated.It notes that the effect of the coupling flutter derivatives on the frequency of the system modes is neglectable,the aerodynamic damping is mainly made up of the terms of direct flutter derivatives and A*1H*3 and the effect of the other coupling flutter derivatives is small.