AEROELASTIC ENERGY MECHANISMS IN THEORY AND DESIGN,

A brief review is given of the background to the present trend to basic reassessment of aeroelastic mechanisms, and some of the factors which complicate these. An earlier analysis based a discussion of those parameters which play a significant role in the flutter mechanism on the energy balance equation, and related the system stability to its capacity for absorbing energy. A criterion of ultimate stability was deduced from an expression of the average energy gain or loss per cycle in a self-oscillation. It is shown now that for a system of n degrees of freedom there are a total of 3n1 such criteria based on total and modal energy balance in both the average and on an instantaneous basis. It is possible to isolate criteria which depend only on the reduced frequency, only on the air speed, on both or on neither. The implications in understanding the basic mechanisms, in assessing the effects of parametric changes, in system analysis, and in system synthesis are outlined in terms of the binary system. Author