热障涂层电涡流检测新变压器模型与信号解耦方法研究

doi:10.3901/JME.2025.12.012

摘要/Abstract

摘要： 热障涂层由陶瓷层、黏结层和基体组成，其厚度均匀性检测是发动机叶片质量控制迫切需求的关键技术。热障涂层具有结构复杂、厚度薄、导电性差且差异小特点，导致信号弱、耦合性很强，因此涂层厚度准确检测难度极大。建立三绕组变压器模型，开展阻抗信号耦合机理及厚度测量方法研究。首先，研究黏结层和基体涡流衰减与扩散特性，引入等效涡流环并运用场路变换和能量等效确定其参数，建立三绕组变压器模型。然后，探究陶瓷层和黏结层厚度信号耦合机理，通过特征匹配、频率调控和涡流环离散分解获取陶瓷层和黏结层厚度信号特征以解耦厚度耦合信号，建立陶瓷层和黏结层厚度测量方法。最后，研制电涡流检测系统实现热障涂层陶瓷层和黏结层厚度的同时准确测量。试验结果表明陶瓷层和黏结层厚度测量相对误差分别小于5.0%和10.3%。

关键词: 热障涂层, 电涡流, 耦合机理, 新变压器模型, 厚度检测系统

Abstract: Thermal barrier coating(TBC) consists of a ceramic coating(TC), a bonding coating(BC), and a substrate. Thickness measurement of TBC plays an important and urgently needed role in quality control of engine blades. TBC has the characteristics of complicated structure, uneven thickness, low conductivity and similar electromagnetic parameters. The resultant signals are weak and strongly coupled. Therefore, it is difficult to accurately detect the coating thickness. A novel three-winding transformer model of eddy current(EC) is established, and the research is conducted on the signal coupling physics and a new method for thickness measurement. Firstly, the attenuation and diffusion characteristics of ECs in each layer of TBC are explored. The equivalent EC ring is introduced, and the parameters are determined through field-circuit transformation and energy equivalent to establish a three-winding transformer model. Secondly, the signal coupling mechanism between TC and BC is explored. The characteristic signals of the thicknesses of TC and BC, are obtained by feature matching, frequency regulation, and discrete decomposition of EC ring, to decouple the thickness signals. Finally, an EC prototype is developed to economically achieve simultaneous and accurate thickness measurements of TC and BC. The results show that the relative errors of TC and BC are less than 5% and 10.3%, respectively.

Key words: thermal barrier coating, eddy current, coupling mechanism, novel transformer model, thickness detecting system

中图分类号:

TG156

李超, 范孟豹, 曹丙花, 孙凤山, 叶波, 严佳航. 热障涂层电涡流检测新变压器模型与信号解耦方法研究[J]. 机械工程学报, 2025, 61(12): 12-25.

LI Chao, FAN Mengbao, CAO Binghua, SUN Fengshan, YE Bo, YAN Jiahang. Study on Novel Transformer Model of Eddy Current Testing and Signal Decoupling of Thermal Barrier Coating[J]. Journal of Mechanical Engineering, 2025, 61(12): 12-25.

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