In this paper, a finite element method is employed to investigate the natural frequencies of twisted rotating composite turbine blades subject to multiple delamination. The turbine blade is idealized as a shallow conical shell model with low aspect ratio. The formulation is based on Mindlins theory, QR iteration and multi-point constraint algorithm for moderate rotational speeds neglecting Coriolis effect. Computer codes are developed and the numerical results obtained for multiple delaminated graphite-epoxy cross-ply composite shallow conical shells are the first known non-dimensional frequencies for the type of analyses carried out here.
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