Research on vibration response of a multi-faulted rotor system using LMD-based time-frequency representation

Abstract

Unbalance, fatigue crack and rotor-stator rub are the three common and important faults in a rotor-bearing system. They are originally interconnected each other, and their vibration behaviors do often show strong nonlinear and transient characteristic, especially when more than one of them coexist in the system. This article is aimed to study the vibration response of the rotor system in presence of multiple rotor faults such as unbalance, crack, and rotor-stator rub, using local mean decomposition-based time-frequency representation. Equations of motion of the multi-faulted Jeffcott rotor, including unbalance, crack, and rub, are presented. By solving the motion equations, steady-state vibration response is obtained in presence of multiple rotor faults. As a comparison, Hilbert-Huang transformation, based on empirical mode decomposition, is also applied to analyze the multi-faults data. By the study some diagnostic recommendations are derived.

Electrical transient modeling for appliance characterization

“…Monitoring electrical loads and systems is particularly one of the areas where transients play a central role. We cite as applications the analysis of disturbances affecting the quality of the electric power system [7,8], fault detection in rotary machines [9,10], and non-intrusive load monitoring (NILM) [11][12][13], a field concerned with extracting individual energy consumption (e.g., of different appliances) from measured total energy consumption (e.g., at main breaker panel).…”

Experimental diagnosis of multiple faults on a rotor-stator system by fast Fourier transform and wavelet scalogram

“…Patel and Darpe [11] numerically and experimentally investigated rotor vibration characteristics of unbalance, crack and rotor-stator rub faults using both classical Jeffcott rotor model and Timoshenko beam element. Despite the abovementioned faults that are partially identifiable using classical methods such as fast Fourier transform (FFT), fault signals in rotors are not often periodic or quasi-periodic in time and regularly give rise to various resonant frequencies for the same set of data (nonlinearity) [13][14][15]. Discretisation techniques and numerical simulation of rotor faults have shifted from classical FFT to new time-frequency analysis algorithms, where the analysis of the behaviour of a system is based on nonlinearity and non-stationary considerations.…”

“…Therefore, a significant effort is devoted to research on time-frequency analysis based on fault diagnosis methods. Vibration analysis techniques, such as the wavelet transform (WT) [12][13][14][15] have been employed to analyse the rotor vibration signals.…”

“…Using local mean decomposition-based time-frequency representation. Jiao et al [13] theoretically studied the vibration response of the rotor system in the presence of multiple rotor faults such as unbalance, crack and rotor-stator rub. Their study revealed that rub and uncracked rotor excites higher frequency components with almost equal periodic modes.…”