Abstract
The rub-impact fault, which occurs in the aeroengine, can cause frequency modulation (FM) in its vibration signal. Oscillated instantaneous frequency (IF) is a phenomenon of such a modulation mode, which carries critical fault information from the aeroengine. In this paper, by using Variational Mode Decomposition (VMD), the vibration signal can be decomposed into several signal components. Two-layer Singular Value Decomposition (SVD) is utilized to reduce the signal noise of each signal component and instantaneous frequency of each signal component. The intra–wave FM feature of the signal are presented through the Hilbert transform (HT) analysis. The proposed method is validated with numerical simulation and then demonstrated on aeroengine data with the rub-impact fault. The proposed method is suitable for the analysis of modulated signals and is a valid tool for detecting the rub-impact faults in aeroengines.
Highlights
Rotating machinery occupies an important place in modern industry [1], including aeroengines, rotating electrical machines and wind turbines, etc
When a rub-impact fault occurs in the rotor system, it will lead to an amplitude modulation (AM) in the vibration signal and the instantaneous frequency (IF) of the fundamental harmonic will fluctuate; the fluctuating frequency of IF is equivalent to the harmonic frequency [7]
The time–frequency diagram obtained by using short-time Fourier transform (STFT) cannot guarantee good frequency resolution and the fast-changing instantaneous frequency can be displayed at the same time, no matter how we adjust the length of the window
Summary
Peng Zhang 1,2 , Shunming Li 1, *, Kun Xu 1, * , Siqi Gong 1, * , Keyi Zhan 2 , Maoxian Shen 2 , Jun Tian 2 and Xin Yuan 2. Sci. Part of the content of this article was published at the “The 12th IEEE Global Reliability & Prognostics and Health Management Conference (IEEE PHM Nanjing 2021)”, and this article has been expanded on the basis of the conference paper: Zhang, P.; Li, S.; Xu, K.; Gong, S.; Zhan, K.; Shen, M.; Tian, J.; Yuan, X. 5 Additional information, including: “At some rotation speeds, the fluctuating frequencies of the instantaneous frequencies are consistent with the fluctuating frequencies on the envelope spectrum” and 6 “By comparing several methods with rub-impact fault data without denoising, when only 1× is decomposed, the proposed method, HHT, and VNCMD can all obtain time–frequency representations of 1×, and the waveform of instantaneous frequency of 1× obtained by the proposed method is better at this time. Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
