An Analysis of the Effect of Centrifugal Force on the Impact Resistance of Composite Fan Blades for Turbo-Fan Engines

An analysis has been conducted to determine the feasibility of composite fan blade for meeting impact resistance requirements for turbo-fan engines.

This report describes the effect of centrifugal force on the impact response of fan blades. Transient deformations of six fan blade models of different materials and sizes generated by bird strike were calculated by finite element method.

It was cleared that global deformation of the blade made of heavy material was appreciably reduced by centrifugal force, but the effect of centrifugal force on the local deformation was small. For the blade made of light materials, e.g. polymer matrix composites, the effect of centrifugal force is less appreciable than for the blade made of heavy materials.

Maximum stress generated by 1.5 lb (680 gram) bird strike is large enough to generate local permanent deformation in the metal blades and to generate global delamination in the polymer matrix composite blades.