Dynamic Characteristics Analysis and Fault Feature Study of Bearings with Compound Defects

Abstract To investigate the dynamic variation patterns of rolling bearings with compound faults, a dynamic finite element model of defective bearings was established in ANSYS based on explicit dynamics algorithms. This model fully considers factors such as bearing rotational speed, load, contact, and friction. The dynamic analysis of rolling bearings with composite faults, involving rolling element and outer raceway dents, was conducted. The study results indicate significant differences in shear stress and vibration acceleration characteristics at different rotational speeds. The higher the speed, the more severe the fluctuations in stress and vibration acceleration, which significantly impacts bearing life. To further extract and analyze fault features, the Variational Mode Decomposition was used to decompose the vibration signals obtained from explicit dynamic simulations, yielding Intrinsic Mode Function (IMF) components at different speeds. By calculating the kurtosis, sample entropy, and envelope entropy of each IMF component, a comprehensive evaluation index was established. The components were then ranked using a weighted average method, selecting those with higher evaluation indices as effective components. After performing a Fast Fourier Transform (FFT) on the effective components, time-domain and frequency-domain analysis successfully extracted crucial information containing bearing fault features. This provides important references for bearing condition monitoring and fault diagnosis.