THE INFLUENCE OF IMPERFECTIONS ON THE EIGENFREQUENCIES OF A ROTATING COMPOSITE SHAFT

Abstract The influence of imperfections of a rotating composite shaft is considered. When the shaft is non-rotating the geometry remains unchanged and the eigenfrequencies depend only on the material stiffness. In high speed applications the eigenfrequencies also depend on the new geometry. The difference between these two cases is negligible, which means that the change in the stiffness has much greater influence than the change in the geometry. The difference between the eigenfrequencies in the x and y directions, Δω, depends on the term used in a Fourier series expansion of the radius. The second cosine term is shown to have the largest influence on the eigenfrequencies and the dependence is almost linear. Imperfections of the types described in this paper have largest influence when the filament winding angle is about 60°.