A HARMONIC FINITE-ELEMENT FOR THE ANALYSIS OF FLEXURAL, TORSIONAL ANDAXIAL ROTORDYNAMIC BEHAVIOR OF BLADE ARRAYS

The aim of this paper is to develop the formulation of a finite elemen t for the study of the axial, torsional and flexural dynamic behavior of a rotating array of blades taking into account the gyroscopic effec t and the centrifugal loadings. The displacements within the element a re described in terms of superposition of the rigid body motion and th e deflections relative to the rigid body configuration. A truncated Fo urier's series has been adopted to approximate the dependence on tange ntial direction of the displacement field while polynomial shape funct ions are employed in the radial direction. Just the zero and one nodal diameter deflections have been considered in the Fourier series as th ey are the only ones coupled to the axial, torsional and flexural beha vior of the disc-shaft system. The element equations of the motion are obtained using a complex co-ordinate formulation. Analytical solution s and experimental results have been compared to the results of the FE M model to test its accuracy. (C) 1997 Academic Press Limited.