On-Board Bearing Prognostics in Aricraft Engine : Enveloping Analysis or FFT (Preprint)
Conference paper Preprint
AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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Prognostics of rolling element bearing mandates detecting bearing defect signatures as early as possible, so that corresponding maintenance can be scheduled and catastrophic machine breakdown can be avoided. Defects can occur in any of the bearing parts, inner and outer race, cage and rolling elements. It is possible to identify the defective component of the bearing based on the specific vibration frequencies that are excited. However, the pattern of vibration spectrum changes as bearing deteriorates through different stages. Depending on which failure stage the bearing is in, different techniques should be adopted to seek signature in different frequency ranges. Techniques such as enveloping analysis that performs in high frequency region apparently requires higher data sampling rate and more expensive data acquisition hardware than those analysis conducted in low frequency region. This paper compares two popular rolling element bearing diagnostics techniques, spectrum analysis in bearing characteristic frequency range and enveloping analysis in high frequency range, using test data from an aircraft engine test rig.
- Machinery and Tools