Performance of an Adaptive Magnetorheological Fluid Mount

2007 ◽  
Author(s):  
Constantin Ciocanel ◽  
The Nguyen ◽  
Christopher Schroeder ◽  
Mohammad H. Elahinia
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Magnetorheological Fluid ◽  
Flow Mode ◽  
Frequency Range ◽  
Governing Equations ◽  
Mr Fluid ◽  
System Parameters ◽  
Force Transmissibility ◽  
Working Frequency

The paper investigates the response of a magnetorheological (MR) fluid based mount that combines the squeeze and flow modes in operation. The mount governing equations are introduced and the effect of system parameters on its performance is analyzed. The proposed design yields a high static and a low dynamic stiffness in the working frequency range of the mount. The overall vibration isolation characteristic of the mount is enhanced if compared to that of existing hydraulic mounts. Displacement and/or force transmissibility can be isolated or significantly reduced, in real time, by controlling the MR fluid yield stress. An embedded electromagnet is used to activate the MR fluid that can work in either squeeze or flow modes, or in both simultaneously. The results indicate that the flow mode is less effective in reducing transmissibility than the squeeze mode. However, when the flow and squeeze modes are both activated, the effect of the flow mode becomes more obvious.

Skyhook Control of a Mixed Mode Magnetorheological Fluid Mount

2010 ◽  
Author(s):  
Shuo Wang ◽  
The Nguyen ◽  
Walter Anderson ◽  
Constantin Ciocanel ◽  
Mohammad Elahinia
Keyword(s):  
Mixed Mode ◽  
Magnetorheological Fluid ◽  
Resonance Peak ◽  
Control Algorithms ◽  
Flow Mode ◽  
Frequency Range ◽  
Mr Fluid ◽  
Working Frequency ◽  
Fluid Dampers ◽  
Mr Effect

Magnetorheological (MR) fluid mounts have their own advantages over the hydraulic mounts because they can provide extra damping and stiffness due to the MR effect. Many papers contribute to the control of MR fluid dampers, while very few papers focus on the control of MR mounts. This paper investigated skyhook control for a mixed mode MR fluid mount. The MR fluid mount can operate in two working modes: flow mode and squeeze mode. The skyhook control algorithms were developed and studied for the flow mode and squeeze mode separately and simultaneously. Simulation results show that the skyhook control can significantly reduce the resonance peak and achieve the lowest transmissibility in the whole working frequency range of the mount. When flow mode and squeeze mode are activated and controlled at the same time, the effect of squeeze mode is more obvious than that of the flow mode.

Experimental Verification of Controllability of a Mixed Mode MR Fluid Mount

2011 ◽  
Author(s):  
Shuo Wang ◽  
Mohammad Elahinia ◽  
The Nguyen
Keyword(s):  
Mixed Mode ◽  
Alternative Energy ◽  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Hybrid Vehicles ◽  
Flow Mode ◽  
Shear Mode ◽  
Mr Fluid ◽  
Set Up ◽  
Different Levels

With the advent of alternative energy and hybrid vehicles come new vibration problems and challenges that require nontraditional solutions. Semi-active vibration isolation devices are preferred to address the problem due to their effectiveness and affordability. A magnetorheological (MR) fluid mount can provide effective vibration isolation for applications such as hybrid vehicles. The MR fluid can produce different levels of damping when exposed to different levels of magnetic field. The fluid can be working in three modes which are the flow mode, shear mode and squeeze mode. A mixed mode MR fluid mount was designed to operate in a combination of the flow mode and the squeeze mode. Each of the working modes and the combined working mode has been studied. The mount’s performance has been verified in simulation and experiments. Based on the simulation and experimental results, it can be seen that the mount can provide a large range of dynamic stiffness. Given this range of dynamic stiffness, a controller has been designed to achieve certain dynamic stiffness at certain frequencies. The experiments are set up to realize the hardware-in-the-loop tests. Results from the experiments show that the mixed mode MR fluid mount is able to achieve desired dynamic stiffness which is directly related to vibration transmissibility.

On the Design and Control of a Squeeze-Flow Mode Magnetorheological Fluid Mount

2007 ◽  
Author(s):  
Constantin Ciocanel ◽  
The Nguyen ◽  
Christopher Schroeder ◽  
Mohammad Elahinia
Keyword(s):  
Vibration Isolation ◽  
Hybrid Control ◽  
Control Strategies ◽  
Dynamic Stiffness ◽  
Squeeze Flow ◽  
Flow Mode ◽  
Force Transmissibility ◽  
Displacement Force ◽  
Vertical Vibrations ◽  
And Control

The paper presents the design and control of a magnetorheological (MR) fluid based mount that combines the squeeze and flow modes in operation. The proposed design yields a high static stiffness and a low dynamic stiffness in the working frequency range of the mount, enhancing the vibration isolation capabilities of the mount compared to existing hydraulic mounts. Vertical vibrations, namely displacement/force transmissibility, can be isolated or significantly reduced, in real time, by controlling the fluid yield stress through an applied electric current. The mount governing equations have been derived and the effect of system parameters on its performance was analyzed. Preliminary results on the implementation of skyhook, groundhook and hybrid control strategies are also presented.

Dynamic characteristics of squeeze-type mount using magnetorheological fluid

2005 ◽  
Vol 219 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Y K Ahn ◽  
J-Y Ha ◽  
Y-H Kim ◽  
B-S Yang ◽  
M Ahmadian ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Experimental Analysis ◽  
Vibration Isolation ◽  
Dynamic Behaviour ◽  
Electrical Current ◽  
Magnetorheological Fluid ◽  
Test Set ◽  
Mr Fluid ◽  
Set Up ◽  
Stiffness And Damping

This paper presents an analytical and experimental analysis of the characteristics of a squeeze-type magnetorheological (MR) mount which can be used for various vibration isolation areas. The concept of the squeeze-type mount and details of the design of a squeeze-type MR mount are discussed. These are followed by a detailed description of the test set-up for evaluating the dynamic behaviour of the mount. A series of tests was conducted on the prototype mount built for this study, in order to characterize the changes occurring as a result of changing electrical current to the mount. The results of this study show that increasing electrical current to the mount, which increases the yield stress of the MR fluid, will result in an increase in both stiffness and damping of the mount. The results also show that the mount hysteresis increases with increase in current to the MR fluid, causing changes in stiffness and damping at different input frequencies.

scholarly journals Characteristic analysis of a new high-static-low-dynamic stiffness vibration isolator based on the buckling circular plate

2020 ◽  
pp. 146134842090486
Author(s):  
Zhirong Yang ◽  
Yan Wang ◽  
Ziming Huang ◽  
Zhushi Rao
Keyword(s):  
Equilibrium Point ◽  
Circular Plate ◽  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Harmonic Balance Method ◽  
Installation Space ◽  
Vibration Isolator ◽  
Characteristic Analysis ◽  
Linear Spring ◽  
Force Transmissibility

The high-static-low-dynamic stiffness vibration isolator has great advantages in vibration isolation because it can decrease the natural frequency of the system while keeping the load capability, but it is usually difficult to implement because of its complex structures and installation space constraints. A high-static-low-dynamic stiffness vibration isolator composed of a buckling circular plate and a traditional linear spring is proposed in this paper. The buckling circular plate works as the negative stiffness corrector paralleled with the linear spring, which can be integrated into the sleeve. If the load is chosen properly, the static equilibrium point will be at the initial quasi-zero stiffness point. However, any changes of the load will lead the equilibrium point deviating from the initial equilibrium point. The nonlinear mathematical model of high-static-low-dynamic stiffness vibration isolator considering load imperfection is developed and its force transmissibility is analyzed with the harmonic balance method and homotopy perturbation method. The influence rule of the system parameters on it is analyzed and the corresponding results show that the force transmissibility will exhibit complicated characteristics, depending on the load imperfection, damper, and excitation force.

A Squeeze-Flow Mode Magnetorheological Mount: Design, Modeling, and Experimental Evaluation

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
T. M. Nguyen ◽  
C. Ciocanel ◽  
M. H. Elahinia
Keyword(s):  
Vibration Isolation ◽  
Magnetic Circuit ◽  
Dynamic Stiffness ◽  
Experimental Results ◽  
Squeeze Flow ◽  
Design Parameters ◽  
Flow Mode ◽  
Wide Range ◽  
Isolation Device ◽  
Stiffness And Damping

This paper presents a dual-mode magnetorheological (MR) fluid mount. Combining the fluid’s flow and squeeze modes of operation gives this MR mount a unique possibility for varying dynamic stiffness and damping. Details on the design of the internal structure of the mount and the magnetic circuit are provided. Simulation and experimental results are presented to show the effectiveness of the magnetic circuit. A mathematical model that combines the behavior of the fluid and the elastomeric parts and takes into account the magnetic activation of the fluid is used to gauge the effect of design parameters on the isolation characteristics of the mount. Experimental results show that in the proposed design, the dynamic stiffness of the mount may be varied over a wide range of frequencies making the mount a unique and versatile vibration isolation device for cases where input excitation occurs over a wide range of frequencies.

scholarly journals Dynamic characterization of controlled multi-channel semi-active magnetorheological fluid mount

2021 ◽  
Vol 12 (2) ◽  
pp. 751-764
Author(s):  
Zhihong Lin ◽  
Mingzhong Wu
Keyword(s):  
High Frequency ◽  
Optimization Design ◽  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Vehicle Model ◽  
Mr Fluid ◽  
Unbalanced Force ◽  
Low Frequency Vibration ◽  
Engine Mount

Abstract. In this paper, a novel structure of a controlled multi-channel semi-active magnetorheological (MR) fluid mount is proposed, including four controlled channels and one rate-dip channel. Firstly, the magnetic circuit analysis, rate-dip channel optimization design, and MR fluid mount damping analysis are given. Secondly, the mathematical model of the controlled multi-channel semi-active MR fluid mount is constructed. We analyze the effect of controlled multi-channel closing on the dynamic characteristics of the mounts and the effect of the presence or absence of the rate-dip channel on the low-frequency isolation of the mount. Finally, the controlled multi-channel semi-active MR fluid mount was applied to the 1/4 vehicle model (a model consisting of an engine, a single engine mount, a single suspension and a vehicle frame), with the transmissibility of the engine relative to the vehicle frame at low frequency and the transmissibility of the engine reciprocating unbalanced force to the vehicle frame magnitude at high frequency as the evaluation index. Numerical simulation shows the following points. (1) The controllable multi-channel semi-active MR fluid mount can achieve adjustable dynamic stiffness and damping with applied 2 A current to different channels. (2) With known external excitation source, applied currents to different controllable channels can achieve the minimum transmissibility and meet the mount wide-frequency vibration isolation requirement, while adding a rate-dip channel can improve the low-frequency vibration isolation performance of the MR fluid mount. (3) Switching and closing different controllable channels in the 1/4 vehicle model can achieve the minimum transmissibility of low-frequency engine vibrations relative to the vehicle frame and high-frequency engine vibrations reciprocating an unbalanced force to the vehicle frame. Therefore, the design of the controllable multi-channel semi-active MR fluid mount can meet the wide-frequency isolation.

scholarly journals Power Flow in a Two-Stage Nonlinear Vibration Isolation System with High-Static-Low-Dynamic Stiffness

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Ze-Qi Lu ◽  
Dong Shao ◽  
Hu Ding ◽  
Li-Qun Chen
Keyword(s):  
Nonlinear Vibration ◽  
Power Flow ◽  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Harmonic Balance Method ◽  
Harmonic Excitation ◽  
Resonant Peak ◽  
Nonlinear Stiffness ◽  
Two Stage ◽  
Force Transmissibility

The manuscript concerns the power flow characterization in a two-stage nonlinear vibration isolator comprising three springs, which are configured so that each stage of the system has a high-static-low-dynamic stiffness. To demonstrate the distinction of evaluation for vibration isolation using power flow, force transmissibility is used for comparison. The dynamic behavior of the isolator subject to harmonic excitation, however, is of interest here. The harmonic balance method (HBM) could be used to analyze the frequency response curve (FRC) of the strong nonlinear vibration system. A suggested stability analysis to distinguish the stable and the unstable HBM solutions is described. Increasing both upper and lower nonlinear stiffness could bend the first resonant peak to the left. The isolation range in the power and the force transmissibility plot could be extended to the lower frequencies when the nonlinear stiffness is increased, but the rate of roll-off for the power transmissibility is twice the rate for the force transmissibility at each horizontal stiffness setting. An explanation for this phenomenon is given in the paper.

Design and Analysis of a High-Static-Low-Dynamic Stiffness Isolator Using the Cam-Roller-Spring Mechanism

2020 ◽  
Vol 142 (2) ◽  
Author(s):  
Yuhui Yao ◽  
Xiaojian Wang ◽  
Hongguang Li
Keyword(s):  
Harmonic Balance ◽  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Damping Ratio ◽  
Harmonic Balance Method ◽  
Interaction Force ◽  
Linear Spring ◽  
Cam Profile ◽  
Force Transmissibility ◽  
Spring Mechanism

Abstract This paper presents a new design of a high-static-low-dynamic stiffness (HSLDS) isolator with an adjustable cam profile. The interaction force between the cam and roller provides the negative stiffness force and the linear spring provides the positive stiffness force in the HSLDS isolator. Unlike previous studies, the cam profile in this paper can be individually designed to meet different working conditions. Firstly, the harmonic balance method is used to acquire the dynamic response of the HSLDS isolator. Then, the effects of the damping ratio, stiffness ratio, and external force amplitude on the frequency response amplitude and force transmissibility are discussed. Finally, the frequency responses of four designed nonlinear HSLDS isolators and a linear isolator are acquired by the numerical method. The results show that the nonlinear isolator begins to achieve vibration isolation at 0.11 Hz and the linear one is 8.9 Hz. The proposed HSLDS isolator realizes lower vibration isolation frequency than the linear isolator.

scholarly journals Methods for Measuring the Dynamic Stiffness of Resilient Rail Fastenings for Low Frequency Vibration Isolation of Railways, Their Problems and Possible Solutions

2005 ◽  
Vol 24 (2) ◽  
pp. 107-115 ◽  
Author(s):  
Chris Morison ◽  
Anbin Wang ◽  
Oliver Bewes
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Inertial Force ◽  
Transport Systems ◽  
Frequency Range ◽  
Low Frequency Vibration ◽  
Urban Rail ◽  
Low Stiffness ◽  
European Standards

Low frequency ground or structure-borne sound and vibration emission from urban rail transport systems can be greatly reduced by reducing the stiffness of the rail fastening. Estimates and models of the efficacy of such systems require accurate measurements of their dynamic stiffness over the frequency range of interest, and European Standards make recommendations for such measurements. This paper describes these methods and their shortcomings when applied to modern complete assemblies with low stiffness, one problem of which is the contribution of inertial forces at frequencies approaching and above the natural resonance of the system. This paper suggests a method for correcting for this inertial force, and tests this correction with the driving point method of dynamic stiffness measurement when applied to the Pandrol VANGUARD resilient rail fastening. The preliminary tests effectively triple the frequency range of valid measurements, a result which could be improved when applied to stiffer systems or with further improvements to the test equipment.

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