Transformer Eddy Current Dampers for the Vibration Control

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Andrea Tonoli ◽  
Nicola Amati ◽  
Mario Silvagni
Keyword(s):  
Vibration Control ◽  
Eddy Current ◽  
Magnetic Circuit ◽  
Design Procedure ◽  
Squeeze Film ◽  
Lateral Vibration ◽  
Geometrical Characteristics ◽  
Squeeze Film Dampers ◽  
Lorentz Forces ◽  
Moving Conductor

Eddy current dampers are promising for the passive and semiactive vibration control of mechanical structures. Among them, the “motional” types are based on Lorentz forces between a moving conductor and a stationary magnetic field. On the contrary, “transformer” ones exploit electromagnetic forces varying the reluctance of the magnetic circuit due to the motion of a part of the damper. Considering the simplicity of the layout, transformer configurations seem to be very promising as alternative to traditional rubber or squeeze film dampers to control the lateral vibration of rotating machines. The aim of the present paper is to investigate the dynamic behavior of transformer eddy current dampers integrated in a mechanical structure. The electromechanical system is modeled using the Lagrange approach in terms of the magnetic flux linkages in the electromagnets. The mathematical models have been experimentally validated using two test benches with different layouts and geometrical characteristics of the magnetic circuit. The modeling approach allows to propose a design procedure of this type of damper.

Transformer Eddy Current Dampers for the Vibration Control of Rotating Machines

2006 ◽  
Author(s):  
Nicola Amati ◽  
Stefano Carabelli ◽  
Pietro Macchi ◽  
Mario Silvani ◽  
Andrea Tonoli
Keyword(s):  
Vibration Control ◽  
Eddy Current ◽  
Magnetic Circuit ◽  
Active Vibration Control ◽  
Design Procedure ◽  
Squeeze Film ◽  
Rotating Machines ◽  
Squeeze Film Dampers ◽  
Active Vibration ◽  
Moving Conductor

Eddy current dampers are promising devices for the passive and semi-active vibration control of mechanical structures. Among them “motional” eddy current dampers are based on the Lorentz forces between a moving conductor and a stationary magnetic field. “Transformer” eddy current dampers are based on the forces that develop in a voltage driven electromagnet when part of the magnetic circuit is movable. Considering the simplicity of the layout, transformer configurations seem to be very promising as alternative to traditional rubber or squeeze film dampers to control the lateral vibration of rotating machines. The aim of the present paper is to investigate the dynamic behavior of “transformer” eddy current dampers integrated in a mechanical structure. To this end the bond graph formalism is adopted with the aim of evidencing the causality effects between the mechanical and electromagnetic parts. The modeling approach allows to propose a design procedure of the damper. The mathematical models have been validated experimentally using two test benches with different layouts and geometrical characteristics of the magnetic circuit.

Vibration Control of a Rotor System Utilizing a Bearing Housing With Controllable Spring Nonlinearity

1994 ◽  
Author(s):  
Baojiang Liu ◽  
Litang Yan ◽  
Qihan Li ◽  
Zigen Zhu
Keyword(s):  
Vibration Control ◽  
Nonlinear Vibration ◽  
Dynamic Behaviour ◽  
Rotor System ◽  
Experimental Results ◽  
Squeeze Film ◽  
Solution Curve ◽  
Operating Process ◽  
Squeeze Film Dampers ◽  
Vibration Performance

On the basis of characteristics of vibration in the rotor system with spring nonlinearity, a new method for vibration control has been developed. In the method, the spring characteristics of a bearing housing are controlled to be of softening nonlinearity when the rotor supported on it is accelerated and to be of hardening one when it is decelerated. So vibratory amplitudes of the rotor system always vary along the smallest solution curve in the whole operating process. A model of vibration of the rotor system supported on the controllable hearing housing is derived. Its dynamic behaviour is predicted and verified by experiments. Both theoretical and experimental results show that not only vibratory amplitudes and transmitted forces are suppressed significantly but also nonlinear vibration performance of the rotor supported on squeeze film dampers, such as “lock up” at rotor pin-pin critical speeds and asynchronous vibration, can be avoided.

scholarly journals Design of a Maglev Inertial Actuator with High Mass Power Ratio for Lateral Vibration Control of Propulsion Shafting

Actuators ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 315
Author(s):  
Qianqian Wu ◽  
Zhihui Liu ◽  
Fengyan An ◽  
Bilong Liu
Keyword(s):  
Vibration Control ◽  
Magnetic Circuit ◽  
High Mass ◽  
Good Effect ◽  
Power Ratio ◽  
Lateral Vibration ◽  
Control Effect ◽  
Output Force ◽  
Inertial Actuator ◽  
Effective Output

The maglev inertial actuators with high power and mass maybe effective for lateral vibration control of a propulsion shafting. But the mass power ratio of the actuators currently in use is too small to meet the requirements. In the paper, a maglev inertial actuator was innovatively designed with high mass power ratio. The structure of the magnetic circuit assembly and the suspending assembly were designed and optimized. To verify the property of the proposed maglev inertial actuator, a prototype with mass less than 8 kg was developed and tests were carried out. The minimum effective output force can reach 200 N within the frequency band of 20–300 Hz. A lateral vibration of a propulsion shafting system was constructed and the active control effect was tested. The experimental results show that the proposed maglev inertial actuator has a good effect on lateral vibration control of shafting.

Investigations of Transient Oscillations of Rotors Supported by Magnetorheological Squeeze Film Dampers Using Bilinear Material to Model the Lubricant

2016 ◽  
Vol 821 ◽  
pp. 309-316
Author(s):  
Jaroslav Zapoměl ◽  
Jan Kozánek ◽  
Petr Ferfecki
Keyword(s):  
Squeeze Film ◽  
Lateral Vibration ◽  
Technological Solution ◽  
Damping Force ◽  
Motion Equations ◽  
Damping Effect ◽  
Squeeze Film Dampers ◽  
Nonlinear Character ◽  
Operating Regimes ◽  
Transient Oscillations

Unbalance of rotors is one of the principal causes of their lateral vibration. A technological solution frequently used to its suppression consists in placing damping devices to the rotor supports. To achieve their optimum performance their damping effect must be controllable. This is offered by squeeze film dampers utilizing the magnetorheological phenomenon to control the damping force. In mathematical models magnetorheological oils are usually represented by Bingham or Herschel-Bulkley theoretical materials. Here the magnetorheological oil is modeled by bilinear material with the yielding shear stress depending on magnetic induction. Its flow curve is continuous which contributes to reducing nonlinear character of the motion equations. The new mathematical model was applied to investigate several operating regimes of rotating machines.

Advanced Multi-Squeeze Film Dampers for Rotor Vibration Control

1991 ◽  
Vol 34 (4) ◽  
pp. 489-496 ◽  
Author(s):  
Hooshang Heshmat ◽  
James F. Walton
Keyword(s):  
Vibration Control ◽  
Squeeze Film ◽  
Rotor Vibration ◽  
Squeeze Film Dampers

The Optimal Design of Squeeze Film Dampers for Flexible Rotor Systems

1988 ◽  
Vol 110 (2) ◽  
pp. 166-174 ◽  
Author(s):  
W. J. Chen ◽  
M. Rajan ◽  
S. D. Rajan ◽  
H. D. Nelson
Keyword(s):  
Design Procedure ◽  
Optimization Techniques ◽  
Squeeze Film ◽  
Design Parameters ◽  
Element Formulation ◽  
Rotor Systems ◽  
Transmitted Force ◽  
Squeeze Film Dampers ◽  
Speed Range ◽  
Damper Design

Optimization techniques are employed to design squeeze film dampers for minimum transmitted load to the bearing and foundation in the operational speed range. The rotor systems are modeled by finite element formulation. The maximum transmitted load in the operational speed range is the objective function that is minimized using mathematical nonlinear programming (NLP) techniques. The damper design parameters are the radius, length, and radial clearance. Stability of the equilibrium solutions are investigated in the design procedure. Design derivatives have been determined in closed form expressions without resolution of the inherently nonlinear problem. A parametric study of the transmitted force is carried out to show the influence of damper parameters on the response and to demonstrate the merits of applying optimization techniques in damper design. Two numerical examples are presented that illustrate the effectiveness of optimizing squeeze film damper designs for reducing transmitted load.

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