helicopter blade stability analysis using aeroelastic frequency response functions

In the present paper, the aeroelastic stability of helicopter rotor blade is determined using aeroelastic frequency response function. the conventional methods of aeroelastic stability usually use an iterative procedure while the present method does not require such approach. aeroelastic frequency response functions are obtained by inverting dynamic stiffness matrix of the aeroelastic system. system response could be obtained through exciting each degree of freedom. the resulting response was then plotted and the behavior of this function was investigated to find out the stability criteria and system natural frequencies. the results of this method are compared with stability boundaries obtained from the conventional p-k method and it can be inferred that, compared to other methods, the present algorithm is of less numerical cost.