AEROELASTIC OSCILLATIONS OF A SEESAW-TYPE OSCILLATOR UNDER STRONG WIND CONDITIONS

This paper is concerned with one-degree-of-freedom aeroelastic oscillations of a seesaw- type structure in a steady wind flow. Here it is assumed that strong wind conditions induce nonlinear aeroelastic stiffness forces that are of the same order of magnitude as the structural stiffness forces. As a model equation for the aeroelastic behaviour of the seesaw-type structure, a strongly nonlinear self-excited oscillator is obtained. The bifurcation and the stability of limit cycles for this equation are studied using a special perturbation method. Both the case with linear structural stiffness and the case with nonlinear structural stiffness are studied. For both cases is assumed a general cubic approximation to describe the aerodynamic coefficient. Conditions for the existence, the stability, and the bifurcation of limit cycles are given.