Equivalent Bird-Strike Test Method and Fixture Design for the Trailing Edge of Aero-Engine Composite Fan Blades

To investigate the response and damage behavior of composite aero-engine blades under bird-strike events, an equivalent bird-strike testing method was proposed in which a component-level flat plate specimen was used to replace a full-scale fan blade. The method aims to reproduce the trailing-edge delamination damage observed in full-scale blades during bird strike. Bird-strike tests and corresponding numerical simulations on the plate specimens under different clamping configurations were conducted, and the impact response characteristics as well as the initiation and propagation processes of delamination were systematically analyzed for each configuration. Based on these results, a component-level equivalent test methodology capable of effectively simulating trailing-edge delamination in blade bird-strike scenarios is proposed. A baseline impact condition that induces single-side trailing-edge delamination in a representative composite laminate is identified, including impact height, impact velocity, and the bird-cut ratio (defined as the percentage of the effective impacting volume of the bird projectile relative to its total volume at the instant of impact). In addition, by comparing test and numerical results under various impact conditions, the accuracy of the numerical model is validated. Using the experimentally validated model, sensitivity analyses were performed with respect to the test parameters (impact height, impact velocity, and bird-cut ratio). The results show that, within the controllable ranges of parameter variation in the tests, the changes in key impact response metrics of the composite plate—namely the peak displacement at the upper trailing edge, the peak displacement at the lower trailing edge, and the displacement difference along the upper edge—are all less than 5% relative to the baseline condition. This study demonstrates that the proposed equivalent testing method enables a composite plate test to replicate the local displacement response and delamination pattern of a full-scale blade under bird strike, and the test outcomes exhibit good robustness.