An impact localization method of composite fan blades based on stress wave features

Impact monitoring in real-time is an effective approach to ensure the integrity and safety of aircraft engine composite fan blades. The changing curvature of composite fan blades and the anisotropic nature of the material make it difficult to achieve accurate impact localization with the existing impact monitoring techniques. In this paper, an impact localization method based on stress wave features is proposed to accurately locate impact sources for composite fan blades. Firstly, a sensor array attached to the surface of the fan blade with variable curvatures is used to record the stress waves caused by the impact. Secondly, an adaptive signal decomposition method is used to decompose the original impact signals to obtain the components at different frequency regions. Thirdly, the features of component within the highest frequency region, having a monotonic attenuation relationship with distance and less influenced by material anisotropy, are extracted and fused. Finally, the improved weighted centroid localization algorithm using the fused feature is used to achieve accurate impact localization. Validation is also conducted on a custom-made experimental blade, achieving an average error of 7.9%. The monitoring results demonstrate that the developed method can achieve high-precision impact localization on composite fan blades and it has practical engineering value for monitoring in aerospace engines.