Eddy current testing in nickel-based superalloy turbine blades: Finite element modeling and tiny crack defects analysis

As the crucial distributed industrial asset of aero engines, the manufacturing quality of turbine blades directly affects the service safety of aircraft engines. During the manufacturing process, cracks may occur in the inner wall of turbine blades, which could present a potential safety hazard for aero engines. However, existing research on eddy current detection for the defects of cracks on the inner wall of nickel-based superalloy turbine blades is relatively limited, especially in finite element modeling and simulation analysis. To design an eddy current probe for the detection of cracks on the inner wall of a blade, a simulation model for eddy current detection of cracks on the back of a nickel-based superalloy plate was established by using the finite element method. A systematic analysis was conducted to investigate the influence of coil and crack parameters, in conjunction with probe configuration, on eddy current detection signals. The selection method of coil parameters and the effect of crack parameters on signals were summarized according to the results. Furthermore, the simulation results demonstrated that the Transmit-Receive (TR) probe exhibited the highest detection sensitivity compared with the absolute probe and the differential probe. Additionally, the addition of a magnetic core was found to significantly improve the detection performance of the TR probe.