Ultrasonic Test for Thermal Barrier Coatings of Aeroengine Turbine Blade

Aeroengine turbine blade is usually working in mal-condition, so the thermal barrier coatings is needed to improve the operational performance. A high-frequency ultrasonic pulse method is researched for the testing needs of the structural state of thermal barrier coatings. By establishing thermal barrier coatings model and simulating the ultrasonic propagation characteristics in thermal barrier coatings, the aliasing situation of the echo of the interfaces is analyzed, and the wave packet decomposition technology is introduced to decompose the aliasing echo signal caused by thin layers and evaluate the structural state of thermal barrier coatings. Finally, numerical simulation results show that the high-frequency ultrasonic pulse reflection method can roughly obtained the information of the first coating layer, while the second coating layer can not be evaluated because of the severely attenuated of coatings.