Jeong, Sena Lee, Yong Bok 2024-01-20T01:32:55Z 2024-01-20T01:32:55Z 2021-09-01 2017-05 1077-5463 https://pubs.kist.re.kr/handle/201004/122780 A hybrid foil-magnetic bearing (HFMB) was successfully studied as a vibration isolator by introducing a sudden imbalance or an unexpected disturbance during turbine/rotor operation. This HFMB is used to achieve stability during transient vibration behavior. The HFMB consists of two oil-free bearing technologies: an active magnetic bearing (AMB) and air foil bearing (AFB). Using both technologies takes advantage of the strengths of each bearing while compensating for their inherent weaknesses. In addition, the HFMB has good dynamic characteristics, and the damping can be adjusted using the appropriate gain selection for the AMB controller. Based on these unique features, dynamic stability can be enhanced, even if a sudden imbalance occurs while the rotor is operating. In this study, a rigid rotor was operated at up to 12,000rpm and tested using a control algorithm to reduce the sudden imbalance vibration amplitudes. The experiment was conducted under the situation that the mass dropped out at 6,000rpm. In order to validate the stability performance of the HFMB with a sudden mass loss, the vibration response results for the AFB and HFMB were compared. When applying the HFMB, the asynchronous vibration was suppressed, and the 1x vibration results showed reductions of almost 30%. When the sudden mass loss occurred, the magnetic control force was remarkably effective at reducing the asynchronous vibration of the rotor supported by the HFMB. In conclusion, it was experimentally verified that using the HFMB made sudden imbalance vibration control possible during rotor operation with an air foil bearing. In this respect, the HFMB has the characteristics of high stiffness/damping, which prevent rubbing and suppress excessive vibration due to a sudden imbalance event. English SAGE PUBLICATIONS LTD CHAMBERED POROUS DAMPER PERFORMANCE SYSTEMS Vibration control of high-speed rotor supported by hybrid foil-magnetic bearing with sudden imbalance Article 10.1177/1077546315592531 1 JOURNAL OF VIBRATION AND CONTROL, v.23, no.8, pp.1296 - 1308 JOURNAL OF VIBRATION AND CONTROL 23 8 1296 1308 scie scopus 000399696600006 2-s2.0-85069640395 Acoustics Engineering, Mechanical Mechanics Acoustics Engineering Mechanics Article CHAMBERED POROUS DAMPER PERFORMANCE SYSTEMS Air foil bearing active magnetic bearing hybrid foil-magnetic bearing sudden imbalance stability