A conforming finite shell element suitable for the analysis of curved twisted fan blades is developed and applied to a number of fan blade models. The element is assumed to be a doubly curved right helicoidal shell, in which the curvature is shallow with respect to the twisted base plane defining the helicoid. Element stiffness and mass formulations are based on Mindlin's theory and include the effects of transverse shear and rotary inertia. The thick shell element has 64 generalized co-ordinates, and by deleting transverse shear effects, a thin shell version of the element having 40 generalized co-ordinates is obtained. The thin shell element is used to predict the natural frequencies and mode shapes of a number of fabricated fan blade structures and the results are correlated with experiment. It is found that the finite element predictions converge very rapidly in a monotonic fashion towards the experimental results, even for coarse finite element meshworks.
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