A FINITE-ELEMENT APPROACH FOR DETERMINING THE FREQUENCIES AND DYNAMIC-RESPONSE OF TWISTED, NONUNIFORM ROTATING BLADES WITH SMALL OR NO PRECONE

The differential equations of motion governing the dynamic response of twisted, nonuniform, rotating blades with small or no precone are dis cretized by a finite element approach. Bending deformations in two dir ections am considered in the formulation while torsional, axial, and w arping deformations are neglected. Coriolis, foreshortening, and other nonlinear effects are not included in the development. Several numeri cal studies are performed to illustrate the applicability of the finit e element formulation and to verify the accuracy of the results. The e ffect of precone on the natural frequencies of the rotating blade is i nvestigated. The dynamic response of a twisted, nonuniform rotating bl ade to arbitrarily applied external loading in two directions is also presented.