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

In order to investigate the response and damage behavior of aero-engine composite fan blades under bird-strike events, an equivalent bird-strike test method is proposed in which component-level flat plate specimens are used to replace full-scale fan blades, with the aim of reproducing the trailing-edge delamination observed in full-scale blades during bird strikes by means of component-level flat plate tests. By carrying out bird-strike tests and numerical simulations of flat plate specimens under different clamping schemes, the impact response characteristics of the specimens and the initiation and propagation of delamination damage under each scheme are systematically analyzed; on this basis, a component-level equivalent test method capable of effectively simulating trailing-edge delamination during the blade bird-strike process is proposed, and the baseline impact conditions that can induce one-sided trailing-edge delamination in typical composite laminates, including impact height, impact velocity and bird-cut ratio, are determined. Moreover, by comparing experimental and numerical results under different impact conditions, the accuracy of the numerical model is verified. On the basis of the validated numerical model, numerical simulations are further used to analyze the sensitivity of the established equivalent test method to the impact parameters, and to quantify the influence of impact height, impact velocity and bird-cut ratio on the impact response of composite flat plates. The results show that the equivalent test method proposed in this paper can reproduce, through composite flat plate tests, the local displacement response and delamination damage modes of full-scale blades under bird strikes, and that the experimental results exhibit good robustness.