Quantitative identification of coating thickness and debonding defects of TBC by pulse phase technology

In order to promote quantitative detection of thermal barrier coating by pulse phase, the pulse phase nondestructive testing model of thermal barrier coating in axisymmetric cylindrical coordinates was established. Temperature field was solved by using a finite volume method in the heat pulse excitation. And the phase of the model was accepted by FFT. The impacts of different factors on the phase were analysised. Based on this, quantitative detection of coating thickness and position of the bonding defect of thermal barrier coating were researched in axisymmetric cylindrical coordinates by using the method of LM. The impacts of different factors on quantitative detection were analysised. The research results show that the recognition accuracy of results are high in different initial assumption and different modulation time when there is no measurement error, the effect of initial assumption and modulation time on quantitative recognition is little, the recognition accuracy of results are high in different uniform temperature measurement error, uniform temperature error would not change the result of recognition, the accuracy of the identification results would decrease with the increase of the random temperature error, but there is still a high recognition accuracy under large random temperature error, the effectiveness of the quantitative identification method was proved.