Electromechanical Dampers for Vibration Control of Structures and Rotors

Tonoli, Andrea; Amati, Nicola; Silvagni, Mario

doi:10.5772/10040

Cited by 7 publications

(6 citation statements)

References 21 publications

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“…Motional actuator, a.k.a. a Lorentz type of an electromagnetic device [15,41] consists of a conductive plate attached to the pipe and moving with it within perpendicular magnetic field. This motion induces eddy currents in plates and a drag force resulting from the Lenz law.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, lateral vibrations change the gap in magnetic circuits, which leads to oscillations of magnetic field in the cores, and consequently, the electromagnetic phenomena of induction and hysteresis, which cause the passive effect impeding the motion. These variations of magnetic flux passing through the cores are the reason to call this actuator the transformer device, also known as the Maxwell device [15,41].…”

Section: Introductionmentioning

confidence: 99%

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Stabilization of a cantilever pipe conveying fluid using electromagnetic actuators of the transformer type

2021

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The article presents an investigation of the stabilization of a cantilever pipe discharging fluid using electromagnetic actuators of the transformer type. With the flow velocity reaching a critical value, the straight equilibrium position of the pipe becomes unstable, and self-excited lateral vibrations arise. Supplying voltage to the actuators yields two opposite effects. First, each of the actuators attracts the pipe, thus introduces the effect of negative stiffness which destabilizes the middle equilibrium. Second, lateral vibrations change the gap in magnetic circuits of the actuators, which leads to oscillations of magnetic field in the cores and the electromagnetic phenomena of induction and hysteresis that impede the motion of the pipe. The combination of these two non-linear effects is ambiguous, so the problem is explored both theoretically and experimentally. First, a mathematical model of the system in form of a partial differential equation governing the dynamics of the pipe coupled with two ordinary differential equations of electro-magnetodynamics of the actuators is presented. Then, the equation of the pipe’s dynamics is discretized using the Galerkin procedure, and the resultant set of ordinary equations is solved numerically. It has been shown that the overall effect of actuators action is positive: the critical flow velocity has been increased and the amplitude of post-critical vibrations reduced. These results have been validated experimentally on a test stand.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Stabilization of a cantilever pipe conveying fluid using electromagnetic actuators of the transformer type

2021

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“…Such actuators are reported to be usually more effective than the dampers of another popular category, i.e. transformer devices [30,31], which showed mediocre effectiveness when applied for the passive stabilization of a pipe with flow [32]. Their numerous advantages make us believe that the obtained results may find other applications involving vibration suppression, which are not necessarily related to the pipes with flow.…”

Section: Introductionmentioning

confidence: 99%

Semi-active stabilisation of a pipe conveying fluid using eddy-current dampers: state-feedback control design, experimental validation

2019

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An application of electromagnetic devices of the motional type (i.e. eddy-current dampers) to improve the dynamic stability of a cantilever pipe discharging fluid is proposed. When the flow velocity reaches a critical value, this system loses stability through the flutter. A contactless damping device is used. This actuator is made of a conducting plate attached to the pipe that moves together with it within the perpendicular magnetic field that is generated by the controlled electromagnets. During the motion the eddy currents in the plate and a resultant drag force of a viscous character are generated. First, an optimal control problem that aims to stabilise the system with the optimal rate of decrease of the system's energy is posed and solved. Then a state-feedback parametrization of the obtained optimal control, which can be used in a closed-loop scheme is proposed. The effectiveness of the designed optimal controller is validated by making a comparison with the corresponding passive solutions on the specially designed and constructed experimental test stand of a pipe conveying air.

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“…The working principle of the passive or semi-active electromechanical dampers [3] is based on the eddy currents [4,5] generated with two different strategies: (i) changing the reluctance of a magnetic circuit or (ii) moving a conductor in a stationary magnetic field.…”

Section: Introductionmentioning

confidence: 99%

A computational fluid dynamics investigation of the segmented integral squeeze film damper

et al. 2019

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Rotor vibration attenuation is achieved with damping devices which work on different, often mutually coupled, physical principles. Squeeze film dampers are damping devices that have been widely used in rotordynamic applications. A new concept of a 5-segmented integral squeeze film damper, in which a flexure pivot tilting pad journal bearing is integrated, was investigated. The damper is studied for the eccentric position between the outer and inner ring of the squeeze film land. The ANSYS CFX software was used for solving the pressure and velocity distribution. The development of the complex three-dimensional computational fluid dynamics model of the squeeze film damper, learning more about the effect of the forces in the damper, and the knowledge about the behaviour of the flow are the principal contributions of this article.

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Electromechanical Dampers for Vibration Control of Structures and Rotors

Cited by 7 publications

References 21 publications

Stabilization of a cantilever pipe conveying fluid using electromagnetic actuators of the transformer type

Stabilization of a cantilever pipe conveying fluid using electromagnetic actuators of the transformer type

Semi-active stabilisation of a pipe conveying fluid using eddy-current dampers: state-feedback control design, experimental validation

A computational fluid dynamics investigation of the segmented integral squeeze film damper

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