Dynamic Modeling and Simulation Analysis of Inter-Shaft Bearings with Local Defects Considering Elasto-Hydrodynamic Lubrication

Abstract

As an important component of large engines, inter-shaft bearing is easily damaged due to its poor working conditions. By analyzing the time–frequency distribution rules of fault signals and the evolution law of micro-faults, the bearing failure mechanism can be revealed, and the bearing failure can be monitored in real time and prevented in advance. For the purpose of studying the mechanism of inter-shaft bearing faults, a 4-DOF (degree of freedom) dynamic model of inter-shaft bearing with local defects considering elasto-hydrodynamic lubrication (EHL) is proposed. Based on the established dynamic model, the impact characteristics and distribution rules of the fault signals of the bearing are accurately simulated, and the evolution law of the micro-faults is also analyzed. The effects of different speeds, loads and defect widths on maximum value (MV), absolute mean value (AMV), effective value (EV), amplitude of square root (AST), kurtosis factor (KF), impulse factor (IF), peak factor (PF) and shape factor (SF) are obtained. The findings show that the vibration amplitude of the bearing increases with the increase in defect size, and the faults are easier to diagnose accordingly. At the same time, PF, KF and IF are very sensitive to the initial failure of bearings. With the development of faults, the overall trend of AMV, AST and EV are relatively stable. The PF is sensitive to the change of rotating speeds and defect widths. The SF is insensitive to the change of rotating speeds, loads and defect widths. This lays a foundation for the research of monitoring and diagnosis methods of aeroengine inter-shaft bearing fault.

Dynamic modelling of deep groove ball bearings with different local defects considering skidding and thermal elastohydrodynamic lubrication

“…According to the series-parallel relation of stiffness, total stiffness can be expressed as Equation (12).…”

“…Subsequently, He et al 11 provided a technique to precisely and quantitatively assess the extent of local faults in bearings by examining the transient energy of fault pulses. Tian et al 12 used REB modelling methods to investigate the characteristic of inter-shaft bearing fault signals and the evolution of micro-faults. Liu et al 13 suggested a novel dynamic modelling approach for analysing REB contact and vibration characteristics during fault evolution.…”

Bibliometric Analysis of Engine Vibration Detection

“…It has been more than 50 years since vibration monitoring was proposed in China [12]. Due to the domestic economic and social construction needs, the total number of power unit assemblers is large and the application demand is great; thus, the domestic researchers have unique insights into the research of vibration monitoring fault diagnosis methods and fault mechanisms [13]. Although the start was lagging behind, after more than 50 years of practice in field fault diagnosis, we have accumulated rich knowledge and experience in unit vibration fault characteristics, and have produced long-term and in-depth research on the generation of these faults and the mechanism of generating vibration [14].…”