A Preliminary Parametric Study of Electrorheological Dampers

1994 ◽  
Vol 116 (3) ◽  
pp. 570-576 ◽  
Author(s):  
Z. Lou ◽  
R. D. Ervin ◽  
F. E. Filisko
Keyword(s):  
Cross Section ◽  
Mixed Mode ◽  
Flow Mode ◽  
Shear Mode ◽  
Zero Field ◽  
Damping Force ◽  
Bingham Plastic ◽  
Control Effectiveness ◽  
Er Damper ◽  
Er Fluid

In approaching the design of an electrorheology-based, semi-active suspension, the electrorheological component (ER damper) can be built as either a flow-mode, shear-mode, or mixed-mode type of damper. The source of damping force in the flow-mode is exclusively from flow-induced pressure drop across a valve, while that in the shear-mode is purely from the shear stress on a sliding surface. The dynamics of the fluid flow are included in the derivation of the zero-field damping forces. The control effectiveness is found to be strongly related to the dynamic constant (which is proportional to the square root of the vibration frequency) and, for shear-and flow-mode dampers, the ratio of the piston area to the cross-section of the ER control gap. To achieve the same performance, a flow-mode ER damper is not as compact and efficient as a shear-mode ER damper. With the same ER damping force, a mixed-mode damper is more compact than a shear-mode damper. However, the mixed-mode damper does not have as a low zero-field damping force as the shear-mode damper. The analysis is based on the assumption that the ER fluid is Bingham plastic.

BINGHAM AND RESPONSE CHARACTERISTICS OF ER FLUIDS IN SHEAR AND FLOW MODES

2001 ◽  
Vol 15 (06n07) ◽  
pp. 1017-1024 ◽  
Author(s):  
H. G. LEE ◽  
S. B. CHOI ◽  
S. S. HAN ◽  
J. H. KIM ◽  
M. S. SUH
Keyword(s):  
Electric Fields ◽  
Flow Mode ◽  
Shear Mode ◽  
Damping Force ◽  
Response Characteristics ◽  
Operating Modes ◽  
Field Dependent ◽  
Different Temperatures ◽  
Er Damper ◽  
Er Fluid

This paper presents field-dependent Bingham and response characteristics of ER fluid under shear and flow modes. Two different types of electroviscometers are designed and manufactured for the shear mode and flow mode, respectively. An ER fluid consisting of soluble chemical starches (particles) and silicon oil is made and its field-dependent yield stress is experimentally distilled at two different temperatures using the electroviscometers. Time responses of the ER fluid to step electric fields are also evaluated under two operating modes. In addition, a cylindrical ER damper, which is operated under the flow mode, is adopted and its measured damping force is compared with predicted one obtained from Bingham model of the shear and flow mode, respectively.

Nondimensional Damping Analysis of Flow-Mode Magnetorheological and Electrorheological Dampers

Aerospace ◽  
2003 ◽  
Author(s):  
Wei Hu ◽  
Norman M. Wereley
Keyword(s):  
Magnetic Circuit ◽  
Design Method ◽  
Damping Coefficient ◽  
Flow Mode ◽  
Shear Mode ◽  
Number Range ◽  
Bingham Plastic ◽  
Bingham Number ◽  
Er Damper ◽  
The Relationship

In an effort to develop a Magnetorheological (MR) and Electrorheological (ER) damper initial design method, a quasi-steady relationship between force and velocity exhibited by a flow-mode MR/ER damper is developed based on a Bingham plastic model and a parallel plate assumption. A nondimensional damping coefficient is described as a nonlinear explicit function of an independent nondimensional Bingham number. Since the nondimensional damping coefficient is not a simple analytical function of the Bingham number, a uniform rational approximation approaches is used to determine the relationship between nondimensional damping coefficient and Bingham number. Approximate linear relationship is obtained in a certain Bingham number range. Thus, the quasi-steady flow mode damping approximately consists of a controllable damping and a linear viscous or post-yield damping, which is similar to the behavior of a shear mode damper. The effect on the nondimensional damping coefficient due to the magnetic circuit is also considered by introducing a ration of the length of active region to the total flow gap length.

NONDIMENSIONAL QUASISTEADY ANALYSIS OF A MAGNETORHEOLOGICAL DASHPOT DAMPER

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1584-1590 ◽  
Author(s):  
YOUNG-TAI CHOI ◽  
NORMAN M. WERELEY
Keyword(s):  
Mixed Mode ◽  
Performance Metrics ◽  
Fluid Velocity ◽  
Hydraulic Cylinder ◽  
Flow Mode ◽  
Damping Capacity ◽  
Shear Mode ◽  
Stress Profile ◽  
Cylinder Wall ◽  
Bingham Plastic

This paper addresses nondimensional analysis of a magnetorheological (MR) dashpot damper. An MR dashpot damper consists of a loosely fitting piston within a hydraulic cylinder or reservoir of MR fluids. The fluid flow within such a damper presents both Poiseuille (flow mode or pressurized flow through the duct) and Couette (shear mode or shear flow due to relative motion between piston and hydraulic cylinder wall) simultaneously. Thus, an MR dashpot damper, which mixes both shear and flow modes of behavior, is called a mixed mode damper. In this study, a quasi-steady analysis of MR dashpot dampers was revisited based on the utilization of the Bingham-plastic constitutive model to assess performance metrics such as damping capacity. For the mixed mode MR damper, key physical quantities are derived: fluid velocity profile, shear stress profile, and damping coefficient. In addition, the plug thickness equation to characterize the relationship between the Bingham number and the plug thickness is constructed. Through computer simulation, damping characteristics of the mixed mode MR dashpot damper are evaluated and compared to the flow mode case.

scholarly journals Flow Mode Magnetorheological Dampers with an Eccentric Gap

2014 ◽  
Vol 6 ◽  
pp. 931683 ◽  
Author(s):  
Young-Tai Choi ◽  
Norman M. Wereley
Keyword(s):  
Constitutive Model ◽  
Mr Damper ◽  
Flow Mode ◽  
Rectangular Duct ◽  
Damping Force ◽  
Bingham Plastic ◽  
Mr Dampers ◽  
Annular Gap ◽  
Field Dependent ◽  
Viscous Field

This paper analyzes flow mode magnetorheological (MR) dampers with an eccentric annular gap (i.e., a nonuniform annular gap). To this end, an MR damper analysis for an eccentric annular gap is constructed based on approximating the eccentric annular gap using a rectangular duct with a variable gap, as well as a Bingham-plastic constitutive model of the MR fluid. Performance of flow mode MR dampers with an eccentric gap was assessed analytically using both field-dependent damping force and damping coefficient, which is the ratio of equivalent viscous field-on damping to field-off damping. In addition, damper capabilities of flow mode MR dampers with an eccentric gap were compared to a concentric gap (i.e., uniform annular gap).

Vibration Control of a Flexible Structure Using ER Dampers

1999 ◽  
Vol 121 (1) ◽  
pp. 134-138 ◽  
Author(s):  
Seung-Bok Choi
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Sliding Mode ◽  
Shear Mode ◽  
Flexible Beam ◽  
Short Columns ◽  
Flexible Beam System ◽  
Er Damper ◽  
External Forces ◽  
Er Fluid

This technical brief addresses the vibration control of a flexible beam structure using ER (electro-rheological) dampers. A clamped-clamped flexible beam system supported by two short columns is considered. An ER damper which is operated in shear mode is designed on the basis of Bingham model of the ER fluid, and attached to the flexible beam. After deriving the governing equation of motion and associated boundary conditions, a sliding mode controller is formulated to effectively suppress the vibration of the beam caused by external forces. In the formulation of the controller, parameter variations such as frequency deviation are treated to take into account the robustness of control system. The effectiveness of the proposed control system is confirmed by both simulation and experimental results.

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.

The Performance Analysis of Electro-Rheological Damper

2011 ◽  
Vol 179-180 ◽  
pp. 443-448 ◽  
Author(s):  
Yong Guang Chen ◽  
Hua Yan
Keyword(s):  
Electric Field ◽  
Applied Electric Field ◽  
Vibration Velocity ◽  
Fluid Viscosity ◽  
Damping Force ◽  
Hydraulic Theory ◽  
Set Up ◽  
Er Damper ◽  
Relationship Of ◽  
Er Fluid

Electro-Rheological (ER) fluid is a smart material. It develops a new path for automotive semi-active intelligent suspension system. The damping force of ER damper can be controlled by applied electric field. Applying the theory of rheodynamics and hydraulic theory, a relationship of damping vs. vibration velocity, electric field strength and gas-filled pressure has been set up. There are three sections of damping force, background damping force of a fluid viscosity, electric damping force of applied electric field and pressure of gas. A new gas-filled ER damper is developed. The main structure parameter of influencing ER damper performance are discussed, some design principles of ER damper are given.

scholarly journals High Loaded Mounts for Vibration Control Using Magnetorheological Fluids: Review of Design Configuration

2015 ◽  
Vol 2015 ◽  
pp. 1-18 ◽  
Author(s):  
Xuan Phu Do ◽  
Seung-Bok Choi
Keyword(s):  
Vibration Control ◽  
Cross Sections ◽  
Operation Mode ◽  
Design Parameters ◽  
Flow Mode ◽  
Shear Mode ◽  
Operational Mode ◽  
Damping Force ◽  
Mr Fluid ◽  
Advantages And Disadvantages

Design configurations of high loaded magnetorheological (MR in short) mounts are reviewed and discussed. The configurations are analyzed on the basis of three operating modes of MR fluid: flow mode, shear mode, and squeeze mode. These modes are significantly important to develop new type of mounts and improve the efficiency of vibration control. In this paper, advantages and disadvantages of each operation mode are analyzed on the basis of ability of designing high loaded mounts. In order for analysis, the field-dependent damping force equations for typical cross sections of mounts are firstly investigated while maintaining original equations of these cross sections. As a subsequent step, simulation tools for the high loaded mounts are investigated and discussed. These tools which are developed from the analyzed method are expressed as functions of various design parameters such as inside pressure, magnetic field, dimension, stiffness, and damping. These tools are essential for accurate design of MR mount and for careful checking of the operation capability before manufacturing the mounts. This paper can provide very useful information and guidelines to determine an appropriate design configuration of high loaded mounts whose vibration control performances depend on the operational mode of MR fluid.

Quasi-Steady Analysis of a Magnetorheological Dashpot Damper

Aerospace ◽  
2004 ◽  
Author(s):  
Young-Tai Choi ◽  
Norman M. Wereley
Keyword(s):  
Mixed Mode ◽  
Shear Flows ◽  
Performance Metrics ◽  
Fluid Velocity ◽  
Flow Mode ◽  
Damping Capacity ◽  
Stress Profile ◽  
Bingham Plastic ◽  
Bingham Number ◽  
Moving Wall

This paper addresses quasi-steady analysis of a magnetorheological (MR) dashpot damper. MR dashpot dampers show mixed fluid mode of flow and shear flows since a dashpot inside dampers works as a piston and a moving wall simultaneously. In this study, quasi-steady analysis of MR dashpot dampers has developed based on the utilization of the Bingham-plastic constitutive model to assess performance metrics such as damping capacity. For the mixed mode MR damper that is the sums of flow and shear flows, fluid velocity profile, shear stress profile, and damping coefficient are theoretically derived. In addition, the preyield thickness equation to characterize the relationship between the Bingham number and the preyield thickness is constructed. Through computer simulation, damping characteristics of the mixed mode MR dashpot damper are evaluated and compared with flow mode case.

A GENERALISED PRESENTATION OF VALVE AND CLUTCH DATA FOR AN ER FLUID, AND PRACTICAL PERFORMANCE PREDICTION METHODOLOGY

1996 ◽  
Vol 10 (23n24) ◽  
pp. 3103-3114 ◽  
Author(s):  
D J PEEL ◽  
R STANWAY ◽  
W A BULLOUGH
Keyword(s):  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Operating Conditions ◽  
Flow Mode ◽  
Constant Field ◽  
Bingham Plastic ◽  
Performance Predictions ◽  
Practical Performance ◽  
Field Excitation ◽  
Er Fluid

In previous papers a technique for comparing the performance of a particular electrorheological (ER) fluid in different situations was derived from steady, laminar, shear and flow mode experimental data and static cell tests. By plotting non-dimensional Hedström Number (He) and Friction Coefficient (Cf) against Reynolds Number (Re) via use of the Bingham plastic constitutive equation, one continuous and overlapping relationship was shown for constant field excitation over a range of operating conditions and geometries. In the present work the same treatment is extended to a different fluid, of higher solid volume fraction and different constituents, which was tested on different instruments at a different uniform temperature, so as to attest the generality of the technique. In doing this the methodology of converting low shear rate Couette viscometer data to practical flow valve performance predictions is illustrated.

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