An Analysis of Impact Resistance of Composite Fan Blade.

An analysis of impact resistance of composite fan blades for turbo-fan engines has been conducted. Analytical models of composite blade of different sizes and materials were composed and impact resistance was evaluated by the analysis. The validity of the analytical model was confirmed by comparison of the analytical result with the experimental result of natural vibration of the titanium blade model of the same configuration as the composite blade models. The transient response produced by simulated bird strike on the blade model was analysed with the finite element method which includes bird impact load model and geometrical nonlinierity. The validity of the analytical method was confirmed by comparing the analytical results with the experimental results of some impact tests of the titanium blade models. The results show that polymer matrix composite blades have much lower impact resistance than titanium blade and it is clear that the composite blade of same size as the titanium blade is entirely broken by the bird strike, and 1.65 and 2.06 times larger size composite blades are partially broken by the bird strike.