ROTOR BLADE VIBRATION MODES AND FREQUENCIES
Abstract
The numerical evaluation has been given for certain exact solutions of the differential equa tion of motion of a flexible rotor blade under the action of centrifugal force and inertia, giving the natural frequencies of free vibration and the deflection curves or modes of the dif ferent possible types of vibration. These numeri cal results apply to various degrees and kinds of blade taper, and they have been tabulated and plotted. From the results for the mathematical taper forms listed, the frequencies of the various odes for non- mathematical taper forms, as used in most actual blades, can be interpolated fairly accurately according to the degree of taper, specified by the distance of the blade centroid from the axis, in terms of the tip radius. Blade root conditions influence the modes and fre quencies. In general these can be covered by the location of the flapping hinge, or the equivalent hinge position for built-in blade roots. Hinge location is one of the variables included in the calculations, so that its effect, which is not very sensitive to taper, can easily be found.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1962
- Accession Number
- AD0410217