TY - JOUR AU - NI, Wenjun AU - ZHANG, Chang PY - 2025 TI - Research on composite failure characteristics of bearings based on ANSYS and VMD JO - Journal of Tsinghua University (Science and Technology) SN - 1000-0054 SP - 364 EP - 375 VL - 65 IS - 2 AB - ObjectiveRolling bearings are a key component in the operation of numerical control machine tool, directly affecting the reliability and safety of the entire equipment. Under large load impacts, defects such as pits, scratches, and spalling can form on the bearing raceway and rolling element surfaces. Compared with a single defect, a composite defect results in a larger impact amplitude in the time-domain waveform and more complex main frequency components in the spectrum. Therefore, it is essential to study the compound failure characteristics of rolling bearings to further clarify their failure mechanisms and dynamic behaviors.MethodsThe present study uses ANSYS Workbench to establish a dynamic simulation model of an angular contact ball bearing with composite faults. The simulation results of the bearing composite fault characteristics were compared with the theoretical calculations. The comparison shows an error of less than 3%, thereby verifying the accuracy of the model. The dynamic response behavior of the composite fault bearing at different rotational speeds was then analyzed. Additionally, a composite bearing fault feature identification method based on optimized variational modal decomposition was proposed. The proposed method can be employed to effectively eliminate noise interference in the extraction of bearing fault features. The original search method of the northern eagle optimization (NGO) algorithm exhibits a linear decreasing trend, which hinders the effective balance between global search and local development capabilities. To address this issue, the positive cosine strategy and position optimization search algorithm are employed to replace the position update method in the NGO algorithm during the search phase, thereby improving the original search method. The improved NGO algorithm is then applied to the adaptive parameter search for VMD. Once the optimal parameters are determined, the simulated vibration signals undergo variational mode decomposition, followed by signal reconstruction of the eigenmode function based on the maximum kurtosis principle, enabling spectral analysis. Furthermore, the rolling bearing accelerated life test dataset from Xi'an Jiaotong University was used for bearing fault feature extraction to verify the effectiveness of the SPNGO-VMD composite fault feature extraction method proposed in this study. Finally, a quantitative comparison is presented to assess the differences in feature extraction performance between SPNGO-VMD and the other methods. The analysis is based on search efficiency, global convergence, and fault feature extraction accuracy, and different methods are evaluated using quantitative indexes.ResultsThe research findings indicate that before and after the defective rolling element passes through the outer ring, the equivalent stress is mainly concentrated at the edge of the outer ring defect. The passage of a rolling element through a defect causes localized stress concentration and release within the bearing, decreasing stress. The VMD optimized by the improved NGO algorithm effectively extracts the characteristic frequency components of the composite faults in the bearings, with the frequency peaks corresponding to the theoretically calculated fault frequencies. The improved algorithm demonstrated better search efficiency, global convergence, and fault feature extraction accuracy than other feature extraction models. The algorithm can consistently find the global optimal solution in fewer iterations, avoiding local optima and extracting fault frequency features with greater accuracy.ConclusionsThe simulation model provides a foundation for the experimental design of defective composite bearings. The study results not only aid in identifying and diagnosing potential faults but also offer a theoretical basis for designing more reliable bearing systems. UR - https://doi.org/10.16511/j.cnki.qhdxxb.2025.21.004 DO - 10.16511/j.cnki.qhdxxb.2025.21.004