A crack detection method for aero-engine blade based on air-flow thermography

Aero-engine blade is one of the core components of aero-engine and its safe service is crucial to the normal operation of aero-engine. Thus, it is very important to localize and quantify cracks of aero-engine blades to prevent safety accidents. To guarantee the structural health of aero-engine blades, the air-flow thermography (AFT) method which has advantages of non-contact, high performance, and sensitivity, was proposed for detection of the blade cracks. Firstly, the theoretical thermal response model was established and the crack simulation models with different depths were constructed. Then a detection system was established to detect the artificial cracks with different depths and orientations. Results showed that the proposed method can effectively quantify the cracks with different depths from 0.2 mm to1.0 mm and characterize the crack orientations. In addition, the natural crack on the blade was detected and the principal component analysis (PCA) method was used to enhance the crack contrast with the background.