University of Twente Student Theses
Estimation of the Frequency Response Function of a defective bearing from a measured uni-axial vibration signal
Harish, Ashuthosh (2021) Estimation of the Frequency Response Function of a defective bearing from a measured uni-axial vibration signal.
|
PDF
4MB |
| Abstract: | The axle bearing transmits the high axle load to the wheelsets while providing a smooth rolling-movement for the wheelsets in a train. The axle bearing's failure may result in unplanned breakdowns, derailment, wear on the wheel profile, damage to the track, and the train. Spalling is one of the significant causes of a failure of the axle bearing. The breakaway of material from the surface of the raceway is known as spalling. Condition monitoring techniques are developed to detect and estimate the size of the spall to mitigate the failure of the axle bearing and improve the uptime of the asset. The bearing's condition monitoring must be done by studying its response to the rolling-element moving over a spall, as bearings are sealed and integrated into the machinery. Among the many condition monitoring techniques available, the most common method is to observe the axle bearing's vibration response to the rolling-element and spall interaction, as this is the least invasive method and is characterized by low sensor cost. The rolling-element and spall interaction results in an excitation pulse. The dynamic vibration response in the frequency domain to this excitation pulse has notches (local minima). The notches caused by the excitation pulse are dependent on the size of the spall and Hertzian contact length, or Hertzian contact length. These notches caused by excitation pulse can be used as a feature to estimate the size of the spall. However, the dynamic response spectrum will also have notches due to the anti-resonances of the bearing. Thus, making it difficult to differentiate between the notches caused by the excitation force pulse (spall size sensitive feature) and the anti-resonance. To precisely extract the notches caused by the excitation pulse in the bearing’s dynamic response spectrum, it is essential to separate the FRF (resonance and anti-resonance frequencies) from the measured dynamic response. The notches (local minima) in the dynamic response spectrum caused by the excitation pulse are dependent on the speed and the load. The notches in the dynamic response spectrum caused by the bearing's anti-resonance are independent of speed and load. Based on the dynamic vibration response properties, three methods are developed to estimate the FRF of a bearing. The three methods are Mean Filter, Kalman Filter implementation, and Ensemble Kalman Filter Implementation. Synthetic data is used to verify the three methods developed to estimate the FRF of a defective bearing. An experimental setup is developed to validate the theory on the dynamic response of a defective bearing and FRF estimation methods. The experimental study showed the theory on the rolling-element, and spall interaction is valid for small spalls (spall size is smaller than the Hertzian contact). However, the theory on the rolling-element spall interaction deviated at higher frequencies for large spalls (spall size is larger than the Hertzian contact). This was because of the damping effect of the lubrication. The results of applying the Mean Filter method on the experimental data and synthetic data show that the Mean Filter successfully estimated the shape (resonance and anti-resonance) of the FRF of a bearing with either large or small spalls. However, fail to estimate the exact amplitude and the unit of the FRF. The Kalman Filter implementation method on the experimental data and synthetic data shows that this method successfully estimates the shape of the FRF for bearings with either large or small spalls. However, it is unable to estimate the amplitude of the FRF precisely. The Ensemble Kalman Filter implementation method successfully estimates the shape and the amplitude of the FRF of a bearing with small spalls. However, this method fails for large spalls at higher frequencies. The scope for future work should focus on developing a more in-depth insight into the dynamic vibration response of bearing to a large spall and irregularly shaped spalls. It is believed that the quantification of the error in defective bearing preparation and experimental setup can further improve the Kalman filter and Ensemble Kalman filter formulation. |
| Item Type: | Essay (Master) |
| Clients: | twente, Enschede, Netherlands SKF, Houten, Netherlands |
| Faculty: | ET: Engineering Technology |
| Subject: | 52 mechanical engineering |
| Programme: | Mechanical Engineering MSc (60439) |
| Link to this item: | https://purl.utwente.nl/essays/85519 |
| Export this item as: | BibTeX EndNote HTML Citation Reference Manager |
Show download statistics for this publication
Show download statistics for this publicationRepository Staff Only: item control page