Attenuation of Sommerfeld effect in an internally damped eccentric shaft-disk system via active magnetic bearings

Jha, Abhishek Kumar; Dasgupta, Sovan Sundar

doi:10.1007/s11012-018-00936-7

Cited by 24 publications

(10 citation statements)

References 25 publications

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“…with the use of a DC-DC buck converter or high-frequency pulse width modulation (PWM) with shunt capacitor. Hundreds of articles and review papers [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]31,36 and many text books [1][2][3][4][5]7,9 describe the preceding analysis and results, in similar or a little different manner. Apparently, the suppression of Sommerfeld effect by increasing the foundation damping is beneficial from the point of system operation and control, as proven by existence of all the operating speeds and also the ability to reach any operating speed directly.…”

Section: A Simple Mathematical Modelmentioning

confidence: 99%

“…There are several methods to eliminate Sommerfeld effect through incorporation of additional hardware, such as switching stiffness, 6,24 active magnetic bearings (AMB), 25 dry friction, 26 magnetorheological damper (MRD), 27,28 tuned mass damper (TMD) or tuned vibration absorber (TVA), 29 nonlinear energy sink (NES), 30 and linear electromechanical vibration absorber (LEVA), 31 to name a few. However, these additional hardware increase installation and maintenance cost, and also the chances of failure due to increased system complexity.…”

Section: Introductionmentioning

confidence: 99%

“…At the outset, it appears that increasing foundation damping, directly or indirectly, is a simple costeffective retro-fit solution to fully or partially suppress the Sommerfeld effect. However, it will be shown that from the energy efficiency viewpoint, this is too impractical, and the additional hardware proposed by so-many researchers, 6,[24][25][26][27][28]31 though they involve onetime installation cost and recurring maintenance cost, are in fact much more practical engineering solutions, if they are tuned to reduce damping in the post-critical speed ranges. In this article, particular emphasis will be given to the role of foundation damping on the characteristics of Sommerfeld effect and the resulting energy efficiency, to firmly establish the counterproductive natures of too little and too much foundation damping.…”

Section: Introductionmentioning

confidence: 99%

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Efficiency considerations for Sommerfeld effect attenuation

Samantaray

2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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In rotating machinery with a flexible foundation used for vibration isolation, the drive (motor) is designed to provide maximum power at the critical speed so that the rotor can be coasted up to a supercritical operating speed. Over the time, rotors develop some degree of unbalance and it may be impossible to balance the rotors in-situ, such as in a wind turbine. Therefore, oversized motors are used in anticipation of some unbalance. To promote passage through resonance, without altering the motor, various kinds of additional hardware and/or control mechanisms have been proposed in the past. On the other hand, simply increasing the foundation (or structural) damping reduces the amplitude of unbalance induced vibrations and the motor power requirement at the critical speed. This appears to be the simplest possible solution and has been proposed in relevant mathematical research. However, it is shown in this article that increasing foundation damping significantly reduces the overall system efficiency at the supercritical operating speed and it should not be at all considered as a meaningful engineering solution. In fact, the loss of efficiency due to the increased foundation damping is so large that it may not be compensated by a redesigned motor.

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Section: A Simple Mathematical Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Efficiency considerations for Sommerfeld effect attenuation

Samantaray

2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…Thus, reducing this effect is extremely important for the smooth operation of the rotors at high speeds. The purpose of the article of Jha and Dasgupta 17 is to reduce the Sommerfeld effect of a system with internal damping of an unbalanced flexible shaft and disk using linearized active magnetic bearings. The characteristic equation of the fifth-order polynomial in rotor speed is obtained by balancing the energy of the input power and the mechanical power dissipated in steady state.…”

Section: Introductionmentioning

confidence: 99%

Dynamic modeling of a non-ideal gyroscopic rotor system with nonlinear damping and nonlinear rigidity of an elastic support

Iskakov¹,

Jamalov

Bissembayeb

et al. 2022

Advances in Mechanical Engineering

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The article considers the effect of joint linear and nonlinear cubic damping on dynamics of a gyroscopic rigid rotor interacting with an electric motor with a rectilinear characteristic, taking into account the nonlinear rigidity of the support material. The method of regulating the control parameter (voltage on the motor), the amplitude of vibration, and the angular velocity of the shaft in the frequency equation, depending on the value of the coefficient of nonlinear cubic damping of the support, offers the most effective options for controlling resonant oscillations of large amplitudes. It is shown that the greater the value of the coefficient of nonlinear cubic damping, the easier it is to control these oscillations. Moreover, it is proved that the Sommerfeld effect (of the first kind) can also be weakened and eliminate with the help of joint linear and nonlinear damping. To do this, in the case of a rigid characteristic of the nonlinear elasticity of the support material, in a rotor system with a nonideal energy source to eliminate the bistability region, that is, jumping effects, more nonlinear damping of support or energy from a nonideal energy source will be required than in the case of an ideal rotor system.

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“…They investigated the complicated nonlinear dynamics near resonances of a rotor-AMB system with 16-pole legs and a time varying stiffness. Jha and Dasgupta [17] proposed an active control scheme through a linearized AMB in order to inhibit the Sommerfeld effect of an internally damped flexible shaft with an eccentric disk mounted at the mid-span. Sun et al [18] discussed a case of an actual AMB system where a typical linear system model and classical linear control theory were utilized in the controller design procedure.…”

Section: Introductionmentioning

confidence: 99%

Rotor Active Magnetic Bearings System Control via a Tuned Nonlinear Saturation Oscillator

2021

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The proposed work focuses on improving the performance of the traditional nonlinear saturation controller (NSC) algorithm. In this work, a tuning mechanism can be implemented by providing the NSC control unit with the measured speed Ω of the rotor from a shaft encoder device in order to introduce a tuned NSC (TNSC). In other words, we are going to tune the NSC's natural frequency at one half of Ω such that Ω = 2 . This TNSC is adopted to reduce the vibratory amplitudes of a 16-pole constant-stiffness rotor-Active magnetic bearings (AMBs) system for a wide range of speeds and eccentricities. The whole controlled system is studied mathematically to seek its approximate solutions via the multiple scales technique. Different relations between the rotor's amplitudes and its parameters are plotted so as to verify the proposed tuning mechanism and its crucial role in improving the NSC's performance.INDEX TERMS Tuned nonlinear saturation controller, Proportional derivative controller, Active magnetic bearings, shaft encoder, multiple scales technique.

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Attenuation of Sommerfeld effect in an internally damped eccentric shaft-disk system via active magnetic bearings

Cited by 24 publications

References 25 publications

Efficiency considerations for Sommerfeld effect attenuation

Efficiency considerations for Sommerfeld effect attenuation

Dynamic modeling of a non-ideal gyroscopic rotor system with nonlinear damping and nonlinear rigidity of an elastic support

Rotor Active Magnetic Bearings System Control via a Tuned Nonlinear Saturation Oscillator

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