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High-speed rotors on gas foil bearings (GFBs) are applications of increasing interest due to their potential to increase the power-toweight ratio in machines and also formulate oil-free design solutions. The gas lubrication principles render lower (compared to oil) power loss and increase the threshold speed of instability in rotating systems. However, self-excited oscillations may still occur at circumferential speeds similar to those in oil-lubricated journal bearings. These oscillations are usually triggered through Hopf bifurcation of a fixed-point equilibrium (balanced rotor) or secondary Hopf bifurcation of periodic limit cycles (unbalanced rotor). In this work, an active gas foil bearing (AGFB) is presented as a novel configuration including several piezoelectric actuators that shape the foil through feedback control. A finite element model for the thin foil mounted in some piezoelectric actuators (PZTs), is developed. Second, the gas-structure interaction is modelled through the Reynolds equation for compressible flow. A simple physical model of a rotating system consisting of a rigid rotor and two identical gas foil bearings is then defined, and the dynamic system is composed with its unique source of nonlinearity to be the impedance forces from the gas to the rotor and the foil. The third milestone includes a linear feedback control scheme to stabilize (pole placement) the dynamic system, linearized around a speed-dependent equilibrium (balanced rotor). Further to that, linear feedback control is applied in the dynamic system utilizing polynomial feedback functions in order to overcome the problem of instability.
Rocznik
Tom
Strony
art. no. e146796
Opis fizyczny
Bibliogr. 28 poz., rys.
Twórcy
autor
- National Technical University of Athens, Athens, Greece
autor
- National Technical University of Athens, Athens, Greece
autor
- National Technical University of Athens, Athens, Greece
Bibliografia
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- [21] E. Estupinan and I. Santos, “Controllable Lubrication for Main Engine Bearings Using Mechanical and Piezoelectric Actuators,” IEEE/ASME Trans. Mechatron., vol. 17, no. 2, pp. 279–287, 2012, doi: 10.1109/TMECH.2010.2099663.
- [22] E.A. Estupinan and I.F. Santos, “Controllable radial oil injection applied to main engine bearings-hybrid bearing configurations and control pressure rules,” Proc. STLE/ASME 2010 International Joint Tribology Conference. STLE/ASME 2010 International Joint Tribology Conference, USA, 2010, pp. 145–147, doi: 10.1115/IJTC2010-41170.
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- [25] P. Papafragkos, I. Gavalas, I. Raptopoulos, and A. Chasalevris, “Optimizing energy dissipation in gas foil bearings to eliminate bifurcations of limit cycles in unbalanced rotor systems,” Nonlinear Dyn., vol. 111, no. 1, pp. 67–95, 2023, doi: 10.1007/s11071-022-07837-1.
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Uwagi
Opracowanie rekordu ze środków MNiSW, umowa nr SONP/SP/546092/2022 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2024).
Typ dokumentu
Bibliografia
Identyfikator YADDA
bwmeta1.element.baztech-a37a736b-657b-4cb7-8e2a-34a05c434c42