Dynamic Stability of Rotating Blades with Geometric Non-Linearity

Abstract The dynamic stability behaviour of a rotating blade subjected to axial periodic forces is studied by Lagrange's equation and a Galerkin finite element method. The effects of geometric non-linearity shear deformation and rotary inertia are considered. The iterative method is used to get the mode shapes and frequencies of the non-linear system. Dynamic instability regions of the blade with different reference amplitudes of vibration are illustrated graphically. The instability regions shift to the side of high frequency ratios and the widths of the regions decrease if the reference amplitude is increased. The increase of the reference amplitude consequently makes the blades more stable.