航空发动机涡轮叶片热障涂层结构状态超声检测方法研究
Ultrasonic Test for Thermal Barrier Coatings of Aeroengine Turbine Blade
-
摘要: 航空发动机涡轮叶片工作环境恶劣,需在外表面涂覆热障涂层提高其使用性能。针对热障涂层结构状态的检测需要,进行了高频超声脉冲反射法的研究。通过建立热障涂层有限元模型,模拟与所研究热障涂层中超声波的传播特性,分析各界面的反射回波的混叠状况,并采用波包分解算法提取反射回波,评价热障涂层的结构状态。数值仿真实验表明:高频超声脉冲反射法可以大致获得第一层涂层的信息,而由于涂层的衰减严重,无法对第二层涂层进行评价。Abstract: 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.