scholarly journals Analysis of a Compact Squeeze Film Damper with Magneto Rheological Fluid

2020 ◽  
Vol 70 (2) ◽  
pp. 122-130
Author(s):  
Rahul Kumar Singh ◽  
Mayank Tiwari ◽  
Anpeksh Ambreesh Saksena ◽  
Aman Srivastava
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Squeeze Film ◽  
Vibration Level ◽  
Mr Fluid ◽  
Squeeze Film Damper ◽  
Rotor Systems ◽  
Jeffcott Rotor ◽  
Magneto Rheological ◽  
Control Feedback

Rotor systems play vital role in many modern day machinery such as turbines, pumps, aeroengines, gyroscopes, to name a few. Due to unavoidable unbalance in the rotor systems, there are lateral and torsional vibrations. Ignoring these effects may cause the system serious damages, which sometimes lead to catastrophic failures. Vibration level in rotor systems is acceptable within a range. Focus in this work is to minimize the vibration level to the acceptable range. One of the ways vibration level can be minimised is by means of providing damping. To accomplish this task in this work a new concept squeeze film damper is made by electro discharge machining which is compact in configuration, is filled with magneto-rheological (MR) fluid and tested out on one support of a Jeffcott rotor. This compact squeeze film damper (SFD) produces damping in a compact volume of the device compared to a conventional SFD. MR fluid is a smart fluid, for which apparent viscosity changes with the application of external magnetic field. This compact damper with MR fluid provides the variable damping force, controlled by an external magnetic field. In this work, proportional controller has been used for providing the control feedback. This MR damper is seen to reduce vibrations in steady state and transient input to the Jeffcott rotor. Parametric study for important design parameters has been done with the help of the simulation model. These controlled dampers can be used for reducing vibrations under different operating conditions and also crossing critical speed.

Sliding Mode Control of Flexible Rotor Using Magneto Rheological Squeeze Film Damper

2012 ◽  
Author(s):  
Masoud Hemmatian ◽  
Abdolreza Ohadi
Keyword(s):  
Control Method ◽  
Sliding Mode ◽  
Open Loop ◽  
Squeeze Film ◽  
Flexible Rotor ◽  
Mr Fluid ◽  
Bingham Plastic ◽  
Squeeze Film Damper ◽  
Model Base ◽  
Magneto Rheological

This study aims to control the vibration of a flexible rotor system using magneto rheological squeeze film damper (MR-SFD). To evaluate the performance of damper, Bingham plastic model is used for MR fluid and the hydrodynamic equation of MR-SFD is presented. The remarkable point about this equation is the necessity of using numerical methods to solve it. These methods are too costly and impossible especially in the simulation of complex rotors and implementation of model base controllers. To fix this issue, an estimated equation is used in this paper for pressure distribution throughout the damper. By integration of this expression, hydrodynamic forces of MR-SFD are calculated as an algebraic equation. Furthermore, sliding mode controller is chosen as robust control method by considering the structural and parametric uncertainties of the system. Study time and frequency responses of flexible rotor in presence of these controllers show a good performance in reducing vibration of shafts midpoint. The results for the open loop system also indicate that changing the stiffness coefficient of elastic foundation and the temperature of MR fluid (as two uncertainties of system) strongly affects the outputs while using sliding mode controllers well increases the robustness of the system.

Controllability of a Magnetorheological Fluid Squeeze Film Damper under Sinusoidal Magnetic Field

2007 ◽  
Vol 334-335 ◽  
pp. 1089-1092 ◽  
Author(s):  
Chang Sheng Zhu
Keyword(s):  
Magnetic Field ◽  
Squeeze Film ◽  
Field Frequency ◽  
Mr Fluid ◽  
Magnetic Field Frequency ◽  
Squeeze Film Damper ◽  
Fluid Damper ◽  
Sinusoidal Magnetic Field ◽  
Mr Fluid Damper ◽  
The Magnetic Field

The controllability of a magnetorheological(MR) fluid squeeze film damper under a sinusoidal magnetic field was experimentally studied on a flexible rotor. It is shown that the frequency of the excitation magnetic field has a great effect on the controllability of the MR fluid damper. As the magnetic field frequency increases, the controllability of the MR fluid damper significantly reduces. There is a maximum frequency of the magnetic field for a given magnetic field strength or a minimum strength of the magnetic field for a given magnetic field frequency to make the dynamic behavior of the MR damper be controllable. When the magnetic field frequency is over the maximum one or the magnetic field strength is less than the minimum one, the controllability of the MR fluid damper almost completely disappears and the dynamic behavior of the MR fluid damper with the sinusoidal magnetic field is the same as that without the magnetic field.

Study of the Performance of Practical Magneto-Rheological Elastomers

2012 ◽  
Vol 430-432 ◽  
pp. 1979-1983
Author(s):  
Wei Bang Feng ◽  
Xue Yang ◽  
Zhi Qiang Lv
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Mechanical Property ◽  
Magnetic Properties ◽  
External Magnetic Field ◽  
Magnetic Particles ◽  
Poor Performance ◽  
Electrical And Magnetic Properties ◽  
Intelligent Material ◽  
Magneto Rheological

Magneto-rheological elastomer( MR elastomer) is an emerging intelligent material made up of macromolecule polymer and magnetic particles. While a promising wide application it has in the fields of warships vibration controlling for its controllable mechanical, electrical and magnetic properties by external magnetic field, design and application of devices based on it are facing great limitations imposed by its poor performance in mechanical properties and magneto effect. Aiming at developing a practical MR elastomer, a new confecting method was proposed in this paper. Then, following this new method and using a specificly designed solidifying matrix, an amido- polyester MR elastomer was developed with its mechanical property systemically explored.

A New Unified Approach for Flow Analysis of Magneto-Rheological Fluids

Aerospace ◽  
2004 ◽  
Author(s):  
Barkan M. Kavlicoglu ◽  
Faramarz Gordaninejad ◽  
Xiaojie Wang ◽  
Gregory Hitchcock
Keyword(s):  
Magnetic Field ◽  
Surface Roughness ◽  
Pressure Loss ◽  
Flow Analysis ◽  
Volumetric Flow Rate ◽  
Mr Fluid ◽  
Mason Number ◽  
Universal Approach ◽  
Shear Yield ◽  
Magneto Rheological

The focus of this study is to develop a new universal approach for the flow analysis of magneto-rheological (MR) fluids through channels. An experimental study is conducted to investigate the relationship between the pressure loss of a MR fluid as a function of the applied magnetic field strength, volumetric flow rate, and surface roughness without utilizing the assumption of shear yield stress. A relation for nondimensional friction factor is developed in terms of Mason number and dimensionless surface roughness. It is demonstrated that the pressure loss across the MR fluid flow channel is significantly affected by the magnetic field and the surface roughness.

scholarly journals Squeeze-Film Damper Technology: Part 1 — Prediction of Finite Length Damper Performance

1983 ◽  
Author(s):  
J. W. Lund ◽  
A. J. Smalley ◽  
J. A. Tecza ◽  
J. F. Walton
Keyword(s):  
Finite Length ◽  
Gas Turbines ◽  
Squeeze Film ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Strongly Coupled ◽  
Squeeze Film Damper ◽  
Rotor Systems ◽  
Squeeze Film Dampers ◽  
Calculation Results

Squeeze-film dampers are commonly used in gas turbine engines and have been applied successfully in a great many new designs, and also as retrofits to older engines. Of the mechanical components in gas turbines, squeeze-film dampers are the least understood. Their behavior is nonlinear and strongly coupled to the dynamics of the rotor systems on which they are installed. The design of these dampers is still largely empirical, although they have been the subject of a large number of past investigations. To describe recent analytical and experimental work in squeeze-film damper technology, two papers are planned. This abstract outlines the first paper, Part 1, which concerns itself with squeeze-film damper analysis. This paper will describe an analysis method and boundary conditions which have been developed recently for modelling dampers, and in particular, will cover the treatment of finite length, feed and drain holes and fluid inertia effects, the latter having been shown recently to be of great importance in predicting rotor system behavior. A computer program that solves the Reynolds equation for the above conditions will be described and sample calculation results presented.

Design of a novel magneto-rheological squeeze-film damper

2006 ◽  
Vol 15 (1) ◽  
pp. 164-170 ◽  
Author(s):  
C Carmignani ◽  
P Forte ◽  
E Rustighi
Keyword(s):  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Magneto Rheological

The Effect of Particle Concentration and Magnetic Field on Tribological Behavior of Magneto-Rheological Fluid

2011 ◽  
Vol 314-316 ◽  
pp. 58-61 ◽  
Author(s):  
Wan Li Song ◽  
Chul Hee Lee ◽  
Seung Bok Choi ◽  
Myeong Woo Cho
Keyword(s):  
Magnetic Field ◽  
Friction Coefficient ◽  
Wear Mechanism ◽  
Particle Concentration ◽  
Tribological Behavior ◽  
Wear Loss ◽  
Wear Properties ◽  
Mr Fluid ◽  
Magneto Rheological ◽  
The Magnetic Field

In this paper, the effect of particle concentration and magnetic field on the tribological behavior of magneto-rheological (MR) fluid is investigated using a pin-on-disc tribometer. The wear loss and friction coefficient are measured to study the friction and wear properties of MR fluid. The morphology of the worn pin is also observed by scanning electron microscope (SEM) in order to analyze the wear mechanism. The results obtained in this work show that the wear loss and friction coefficient decrease with increasing particle concentration under the magnetic field. Furthermore, it is demonstrated that the magnetic field has a significant effect on improving tribological properties of MR fluid, especially the one with high particle concentration. The predominant wear mechanism of the MR fluid has been identified as abrasive wear.

scholarly journals Parameter Analysis of an Intershaft Dual-Rotor with the Application of Squeeze Film Dampers

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Huizheng Chen ◽  
Shun Zhong ◽  
Zhenyong Lu ◽  
Yushu Chen ◽  
Xiyu Liu
Keyword(s):  
Vibration Suppression ◽  
Rotor System ◽  
Parameter Analysis ◽  
Dynamical Analysis ◽  
Squeeze Film ◽  
Physical Parameters ◽  
Squeeze Film Damper ◽  
Rotor Systems ◽  
Squeeze Film Dampers ◽  
Frequency Curves

The squeeze film damper is usually adopted in the rotor system to suppress the vibrating motion of the rotor system. In this work, not only are the physical parameters of the squeeze film damper analyzed but also the system parameters, like the number of squeeze film dampers used and squeeze film damper implementation positions, are analyzed. The amplitude-frequency curves are obtained by conducting the simulation of a dual-rotor, intershaft, and oil film force concatenated model. Through the analysis and comparisons of the results, the vibration suppression effects of the squeeze film damper with different parameter configurations are analyzed and summarized. This work contributes to further optimization and dynamical analysis work on rotor systems with the application of the squeeze film damper.

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