Huang, Yi, Hailiang Wang, Weiqiang Chen, Shuncong Zhong, Tingting Shi, Caihong Zhuang, Fuwei Sun, Yonglin Huang, and Zhenghao Zhang. "Terahertz non-destructive testing of thin self-lubricating bearing coating thickness based on SOMP sparse representation." Infrared Physics & Technology (2025): 106223.
Abstract
The thickness of aviation solid thin self-lubricating bearing coatings gradually decreases during wear, which leads to severe echo overlapping in terahertz non-destructive testing. This adversely affects the extraction of coating thickness information. In this paper, a thin coating thickness measurement method that integrates secondary orthogonal matching pursuit (SOMP) sparse representation with the time-of-flight (TOF) is proposed. The propagation characteristics of terahertz waves are firstly investigated, and the convolutional dictionary matrix is constructed based on the reference signal. Subsequently, a series of suboptimal atoms are selected by maximizing the inner product between the reflected signal and the column vector. On this basis, the optimal atoms are further identified using the minimum envelope entropy index to reconstruct the impulse response. The coating thickness is finally quantitatively calculated using the TOF method. The experiments demonstrate that this method can detect coatings thinner than 15 μm with a relative error below 5 %. This study is expected to provide an effective method for accurately measuring the thickness of thin self-lubricating bearing coatings.
No comments:
Post a Comment