Abstract

As a promising nondestructive testing (NDT) technique with a very adaptive physical modeling of wave transmission process, terahertz technology is used for the detection and characterization of nonpolar materials and the evaluation of layered and/or defective structures. THz-TDS can also be used to perform spectroscopic analysis and detect structural defects in thermal barrier coatings (TBCs) of aero-engines. Although it is generally difficult to measure the structure of the thin oxide layer of the thermal barrier coatings whose thickness is generally lower than 30 µm (the current axial resolution of the THz-TDS cannot exceed 30 µm). We were able to complete the detection of the oxide layer within 1–29 µm through simulation by using the SWT-BP algorithm. In this study, the analysis was performed on real-world samples, the fitting degree of the SWT-BP algorithm reached 0.77, and the minimum prediction error was less than 0.1 µm. The paper also put forward some improvement measures about the experimental results.

© 2024 Optica Publishing Group

Thin thermally grown oxide thickness detection in thermal barrier coatings based on SWT-BP neural network algorithm and terahertz technology

Manting Luo, Shuncong Zhong, Ligang Yao, Wanli Tu, Walter Nsengiyumva, and Weiqiang Chen
Appl. Opt. 59(13) 4097-4104 (2020)

In-situ evaluation of porosity in thermal barrier coatings based on the broadening of terahertz time-domain pulses: simulation and experimental investigations

Dongdong Ye, Weize Wang, Haiting Zhou, Jibo Huang, Wenchao Wu, Hanhong Gong, and Zhen Li
Opt. Express 27(20) 28150-28165 (2019)

Detection method and instrument of interfacial debonding inside a thermal barrier coating based on fluorescence imaging

Zong Wang, Yanheng Zhang, Jinli Guo, Shijie Zhang, and Wei Qiu
Appl. Opt. 61(18) 5401-5408 (2022)

Pulsed terahertz spectroscopy combined with hybrid machine learning approaches for structural health monitoring of multilayer thermal barrier coatings

Dongdong Ye, Weize Wang, Changdong Yin, Zhou Xu, Haiting Zhou, Huanjie Fang, Yuanjun Li, and Jibo Huang
Opt. Express 28(23) 34875-34893 (2020)

Pulsed-terahertz reflectometry for health monitoring of ceramic thermal barrier coatings

Chia-Chu Chen, Dong-Joon Lee, Tresa Pollock, and John F. Whitaker
Opt. Express 18(4) 3477-3486 (2010)