Active vibrations control of journal bearings with the use of piezoactuators

Tůma, Jiří; Šimek, Jiřı́; Škuta, Jaromír; Los, Jaroslav

doi:10.1016/j.ymssp.2012.11.010

Cited by 47 publications

(25 citation statements)

References 10 publications

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“…Riemann et al [27] took a step further and managed to control the oil-whip instability using a -synthesis control, extending the rotor operational range from 42 Hz (oil-whip threshold) up to 60 Hz in an experimental test rig; a magnetic actuator was used as well. Tuma et al [28] extended the instability threshold of a rigid rotor from 3400 rpm to 7300 rpm using two piezoactuators at the bearing bushing and a simple proportional controller.…”

Section: Introductionmentioning

confidence: 99%

On the Instability Threshold of Journal Bearing Supported Rotors

Mendes

Cavalca

2014

International Journal of Rotating Machinery

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Journal bearing supported rotors present two kinds of self-excited vibrations: oil-whirl and oil-whip. The first one is commonly masked by the rotor unbalance, hence being rarely associated with instability problems. Oil-whip is a severe vibration which occurs when the oil-whirl frequency coincides with the first flexural natural frequency of the shaft. In many cases, oil-whip is the only fluid-induced instability considered during the design stage; however, experimental evidences have shown that the instability threshold may occur much sooner, demanding a better comprehension of the instability mechanism. In this context, numerical simulations were made in order to improve the identification of the instability threshold for two test rig configurations: one on which the instability occurs on the oil-whip frequency, and another which became unstable before this threshold. Therefore, the main contribution of this paper is to present an investigation of two different thresholds of fluid-induced instabilities and their detectability on design stage simulations based on rotordynamic analysis using linear speed dependent coefficients for the bearings.

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Section: Introductionmentioning

confidence: 99%

On the Instability Threshold of Journal Bearing Supported Rotors

Mendes

Cavalca

2014

International Journal of Rotating Machinery

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“…7). The stand is similar to Bently Nevada Rotorkit but there are differences like using different kind of sensors and using two cylindrical hydrodynamic journal bearings, Tůma et al (2012Tůma et al ( , 2013. …”

Section: Simulation Study Of the Model Behaviourmentioning

confidence: 99%

“…It is assumed that the carrier ring is a movable part in two perpendicular directions while rotor is rotating. The carrier ring position is controlled by the piezoactuators according to the proximity probe signals, which are a part of the closed loop including a controller, Šimek et al , (2007), Tůma et al (2013). There are many ways how to model a rotor system, but this paper prefers an approach, which is based on the concept developed by Muszynska (1986Muszynska ( , 2005 and Bently et al (1986), who were supported by Bently Rotor Dynamics Research Corporation or on the lubricant flow prediction using a FE method for Reynolds equation solution, Svoboda (2007).…”

Section: Introductionmentioning

confidence: 99%

Use of Complex Signals in Modelling of Journal Bearings

Wagnerova

Tůma

2015

IFAC-PapersOnLine

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There are many ways how to model a rotor system with journal bearings, but this paper prefers an approach, which is based on the concept developed by Muszynska (1986). In contrast to the others, that prefer the lubricant flow prediction using a FE method, the Muszynska model can be employed to simulate the behaviour of a journal vibration active control system by manipulating the sleeve position by piezoactuators, which are a part of the closed loop composed of proximity probes and a controller. The paper is focused on the problem how to simulate behaviour of system and to estimate the true values of the simulation model parameters.

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“…A quite complete overview of the experimental and theoretical achievements on mechatronics applied to controllable journal bearings can be found in [5]. Many concepts for bearing adjustability/control utilize active oil injection [6][7][8] while other proposed concepts incorporating movable bearing pads, among others the very recent [9][10][11][12], the application of external forces in the bearing shell or the journal, for example magnetic [13][14][15][16], or piezo-mechanical [17][18][19] without changing the bearing's clearance geometry.…”

Section: Introductionmentioning

confidence: 99%