Design Optimization of a Bi-Fold Magnetorheological Damper Subject to Impact Loads

2017 ◽  
Author(s):  
Muftah Saleh ◽  
Ramin Sedaghati ◽  
Rama Bhat
Keyword(s):  
Magnetic Field ◽  
Design Optimization ◽  
Impact Velocity ◽  
Dynamic Range ◽  
Magnetorheological Damper ◽  
Damping Force ◽  
Mr Fluid ◽  
Bingham Plastic ◽  
Turbulent Condition ◽  
The Impact

Dynamic range (ratio of the maximum on-state damping force to the off-state damping force), is an important index characteristic of the performance of the Magnetorheological Energy Absorbers (MREAs). In high speed impact, the dynamic range may fall into the uncontrollable zone (≤ 1) due to the increase in the off-state damping force which is associated with the transition of the flow from laminar to turbulent condition. Therefore, it is of paramount importance to design optimize the MREA in order to increase its dynamic range while accommodating the geometry, MR fluid flow and magnetic field constraints. In this study, a design optimization problem has been formulated to optimally design a bi-fold MREA to comply with the helicopter crashworthiness specifications for lightweight civilian helicopters. It is required to have a minimum dynamic range of 2 at 5 m/s impact velocity while satisfying the constraints imposed due to the geometry, volume of the device, magnetic field and the flow of the magnetorheological fluid in the MR valve. Meanwhile in order to comply with the helicopter crashworthiness requirement, the MREA device should be designed to generate 15 kN field-off damping force at the design impact velocity if the MREA is to be integrated with skid landing gear systems. The magneto-static analysis of the MREA valve has been conducted analytically using simplified assumptions in order to obtain the relation between induced magnetic flux in the MR fluid gaps in active regions versus the applied current and MREA valve geometrical parameters. Both Bingham plastic models, with and without minor loss factors, have been utilized to derive the dynamic range and the results are compared in terms of the generated off-state damping force, on-state damping force, and dynamic range. The Bingham plastic model with minor loss coefficients was found to be more accurate due to the turbulent condition in the MREA caused by the impact. Finally, the performance of the optimized bi-fold MREA has been evaluated under different impact speeds.

scholarly journals A smart passive MR damper with a hybrid powering system for impact mitigation: An experimental study

2021 ◽  
pp. 1045389X2098808
Author(s):  
S. Jin ◽  
L. Deng ◽  
J. Yang ◽  
S. Sun ◽  
D. Ning ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Mr Damper ◽  
Damping Force ◽  
Softening Effect ◽  
Impact Speed ◽  
Impact Mitigation ◽  
Passive Damper ◽  
Comparison Results ◽  
Wide Range ◽  
The Impact

This paper presents a smart passive MR damper with fast-responsive characteristics for impact mitigation. The hybrid powering system of the MR damper, composed of batteries and self-powering component, enables the damping of the MR damper to be negatively proportional to the impact velocity, which is called rate-dependent softening effect. This effect can keep the damping force as the maximum allowable constant force under different impact speed and thus improve the efficiency of the shock energy mitigation. The structure, prototype and working principle of the new MR damper are presented firstly. Then a vibration platform was used to characterize the dynamic property and the self-powering capability of the new MR damper. The impact mitigation performance of the new MR damper was evaluated using a drop hammer and compared with a passive damper. The comparison results demonstrate that the damping force generated by the new MR damper can be constant over a large range of impact velocity while the passive damper cannot. The special characteristics of the new MR damper can improve its energy dissipation efficiency over a wide range of impact speed and keep occupants and mechanical structures safe.

scholarly journals Design and multi-physics optimization of a novel magnetorheological damper with a variable resistance gap

2016 ◽  
Vol 231 (17) ◽  
pp. 3152-3168 ◽  
Author(s):  
Jiajia Zheng ◽  
Yancheng Li ◽  
Jiong Wang
Keyword(s):  
Optimization Problem ◽  
Dynamic Range ◽  
Mr Damper ◽  
Magnetorheological Damper ◽  
Voltage Source ◽  
Damping Force ◽  
Variable Resistance ◽  
Design Variables ◽  
Electromagnetic Coils ◽  
Vibration Performance

This paper presents the design and multi-physics optimization of a novel multi-coil magnetorheological (MR) damper with a variable resistance gap (VRG-MMD). Enabling four electromagnetic coils (EMs) with individual exciting currents, a simplified magnetic equivalent circuit was presented and the magnetic flux generated by each voltage source passing through each active gap was calculated as vector operations. To design the optimal geometry of the VRG-MMD, the multi-physics optimization problem including electromagnetics and fluid dynamics has been formulated as a multi-objective function with weighting ratios among total damping force, dynamic range, and inductive time constant. Based on the selected design variables (DVs), six cases with different weighting ratios were optimized using Bound Optimization BY Quadratic Approximation (BOBYQA) technique. Finally, the vibration performance of the optimal VRG-MMD subjected to sinusoidal and triangle displacement excitations was compared to that of the typical multi-coil MR damper.

scholarly journals Design and Multiobjective Optimization of Magnetorheological Damper considering the Consistency of Magnetic Flux Density

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Zhizhen Dong ◽  
Zhimin Feng ◽  
Yuehua Chen ◽  
Kefan Yu ◽  
Gang Zhang
Keyword(s):  
Magnetic Flux ◽  
Multiobjective Optimization ◽  
Flux Density ◽  
Optimization Design ◽  
Dynamic Range ◽  
Mr Damper ◽  
Magnetorheological Damper ◽  
Magnetic Flux Density ◽  
Damping Force ◽  
Mr Dampers

The consistency of magnetic flux density of damping gap (CMDG) represents the balancing magnetic flux density in each damping gap of magnetorheological (MR) dampers. It can make influences on the performances of MR dampers and the accuracy of relevant objective functions. In order to improve the mechanical performances of the MR damper with a two-stage coil, the function for calculating CMDG needs to be found. By establishing an equivalent magnetic circuit model of the MR damper, the CMDG function is derived. Then, the multiobjective optimization function and the working flow of optimal design are presented by combining the parallel-plate model of the MR damper with the function posed before. Taking the damping force, the dynamic range, the response time, and the CMDG as the optimization objective, and the external geometric dimensions of the SG-MRD60 damper as the bound variable, this paper optimizes the internal geometric dimensions of MR damper by using a NSGA-III algorithm on the PlatEMO platform. The results show that the obtained scheme in Pareto-optimal solutions has existed with better performance than that of SG-MRD60 scheme. According to the results of the finite element analysis, the multiobjective optimization design including the CMDG function can improve the uniformity of magnetic flux density of the MR damper in damping gap, which meets the requirements of manufacture and application.

Magneto-Rheological (MR) Damper Design for High-Flowrate Suspensions

2013 ◽  
Author(s):  
Riaan F. Meeser ◽  
P. Schalk Els ◽  
Sudhir Kaul
Keyword(s):  
Mr Damper ◽  
Damping Force ◽  
Mr Fluid ◽  
Bingham Plastic ◽  
Damping Characteristics ◽  
Final Design ◽  
Variable Damping ◽  
Input Variables ◽  
Damper Design ◽  
Magneto Rheological

This paper presents the design of a magneto-rheological (MR) damper for an off-road vehicle where large suspension travel and high flow rates, as compared to typical passenger car suspensions, are required. The MR damper is expected to enhance the capability of the suspension system by allowing variable damping due to inherent properties of the MR fluid. MR fluids exhibit a reversible behavior that can be controlled with the intensity of a magnetic field, allowing a change in the effective viscosity and thereby in the damping characteristics of the fluid. A mathematical model of the proposed damper has been developed using the Bingham plastic model so as to determine the necessary geometry for the damper designed in this study, using the fluid flow rate and current to the electromagnet as the input variables. The model is used to compute the damping force, and the analytical results show that the designed MR damper provides the required range of damping force for the specific vehicle setup that is being used for this study. A valve-mode MR fluid channel has been designed such that the required minimum damping is reached in the off-state, and the desired maximum damping is reached in the on-state. For manufacturing and size considerations, the final design incorporates a triple pass layout with the MR fluid flowing through the three passages that are arranged in an S-shape so as to minimize the cross section of the electromagnet core.

Design and Performance Verification of Variable Dampers Using MR Fluid

2003 ◽  
Author(s):  
Toshihiko Shiraishi ◽  
Tomoya Sakuma ◽  
Shin Morishita
Keyword(s):  
Dynamic Range ◽  
Mr Damper ◽  
Experimental Result ◽  
Damping Force ◽  
Mr Fluid ◽  
Mr Dampers ◽  
Piston Speed ◽  
Analytical Result ◽  
And Performance ◽  
Good Agreement

Two typical types of MR damper were proposed, where the orifice for MR fluid was designed to place between the piston and the cylinder in one type, and to place on the piston in the other type. In the former design, MR fluid was expected to be subjected to shear flow in the orifice, and subjected to Poiseuille flow in the latter design. The damping force of MR dampers was experimentally measured under various conditions of piston speed, piston amplitude and applied electric current to the magnetic coil. The experimental results showed that the maximum damping force were almost the same in both types of damper under the same conditions, except for case under very little amplitude. It was also shown that typical characteristics of MR damper depended on the clearance of orifice and air volume in MR dampers, and the optimal design for the dynamic range of damping force existed in relation to the clearance of orifice. The experimental result of the damping force of these dampers showed good agreement with the analytical result.

Quasi-Steady Herschel-Bulkley Analysis of Magnetorheological Dampers With Preyield Viscosity

Aerospace ◽  
2005 ◽  
Author(s):  
Sung-Ryong Hong ◽  
Shaju John ◽  
Norman M. Wereley
Keyword(s):  
Yield Stress ◽  
Power Law ◽  
Performance Metrics ◽  
Dynamic Range ◽  
Fluid Velocity ◽  
Constitutive Behavior ◽  
Flow Mode ◽  
Damping Capacity ◽  
Mr Fluid ◽  
Bingham Plastic

A magnetorheological (MR) fluid, modeled as a Bingham-plastic material, is characterized by a field dependent yield stress, and a (nearly constant) postyield plastic viscosity. Based on viscometric measurements, such a Bingham-plastic model is an idealization to physical magnetorheological behavior, albeit a useful one. A better approximation involves modifying both the preyield and postyield constitutive behavior as follows: (1) assume a high viscosity preyield behavior over a low shear rate range below the yield stress, and (2) assume a power law fluid (i.e., variable viscosity) above the yield stress that accounts for the shear thinning behavior exhibited by MR fluids above the yield stress. Such an idealization to the MR fluid’s constitutive behavior is called a viscous-power law model, or a Herschel-Bulkley model with preyield viscosity. This study develops analytical quasi-steady analysis for such a constitutive MR fluid behavior applied to a flow mode MR damper. Closed form solutions for the fluid velocity, as well as key performance metrics such as damping capacity and dynamic range (ratio of field on to field off force). Also, specializations to existing models such as the Herschel-Bulkley, the Biviscous, and the Bingham-plastic models, are shown to be easily captured by this model when physical constraints (idealizations) are placed on the rheological behavior of the MR fluid.

Quasi-Steady Axisymmetric Bingham-Plastic Model of Magnetorheological Flow Damper Behavior

Aerospace ◽  
2005 ◽  
Author(s):  
Jin-Hyeong Yoo ◽  
Norman M. Wereley
Keyword(s):  
Closed Form ◽  
Yield Stress ◽  
Dynamic Range ◽  
Closed Form Solution ◽  
Form Solution ◽  
Damping Capacity ◽  
Stress Profile ◽  
Mr Fluid ◽  
Bingham Plastic ◽  
Closed Form Solutions

A typical magnetorheological (MR) flow mode damper consists of a piston attached to a shaft that travels in a tightly fitting hydraulic cylinder. The piston motion makes fluid flow through an annular valve in the MR damper. An electro-magnet applies magnetic field to the MR fluid as it flows through the MR valve, and changes its yield stress. An MR fluid, modeled as a Bingham-plastic material, is characterized by a field dependent yield stress, and a (nearly constant) postyield plastic viscosity. Although the analysis of such an annular MR valve is well understood, a closed form solution for the damping capacity of a damper using such an MR valve has proven to be elusive. Closed form solutions for the velocity and shear stress profile across the annular gap are well known. However, the location of the plug must be computed numerically. As a result, closed form solutions for the dynamic range (ratio of field on to field off damper force) cannot be derived. Instead of this conventional theoretic procedure, an approximated closed form solution for a dampers dynamic range, damping capacity and other key performance metrics is derived. And the approximated solution is used to validate a rectangular duct simplified analysis of MR valves for small gap condition. These approximated equations are derived, and the approximation error is also provided.

Changes in the Resistance Force of a Magneto-Rheological Shock Absorber Induced by a Magnetic Field

2018 ◽  
Vol 915 ◽  
pp. 39-44
Author(s):  
Tatsuo Sawada ◽  
Takuma Endo ◽  
Yuzo Shimizu ◽  
Hitoshi Nishida
Keyword(s):  
Magnetic Field ◽  
Fluid Flow ◽  
Shear Flow ◽  
Applied Magnetic Field ◽  
Shock Absorber ◽  
Plug Flow ◽  
Resistance Force ◽  
Mr Fluid ◽  
Bingham Plastic ◽  
Magneto Rheological

In this study, we report the theoretical resistance force of a magneto-rheological (MR) shock absorber. We use the Bingham plastic model to theoretically represent the dynamic behavior of MR fluid flow in a circular pipe under the effect of a magnetic field. Because an MR fluid has yield stresses, the flow is divided into two regions: shear flow and plug flow. We reveal the relation between the resistance force of the MR shock absorber and the applied magnetic field. We conduct experiments and compare the experimental and analytical results to verify the theoretical approach.

Experimental Evaluation of Magnetorheological Damper Characteristics for Vibration Analysis

2018 ◽  
Vol 10 (1) ◽  
Author(s):  
S. Siva Kumar ◽  
K.S. Raj Kumar ◽  
Navaneet Kumar
Keyword(s):  
Vibration Isolation ◽  
Mr Damper ◽  
Magnetorheological Damper ◽  
Damping Force ◽  
Mr Fluid ◽  
Damping Characteristics ◽  
Fluid Damper ◽  
Mr Fluid Damper ◽  
Stiffness And Damping ◽  
Theoretical Results

Magnetorheological (MR) fluid damper has been designed, fabricated and tested to find the stiffness and damping characteristics. Experimentally the MR damper has been tested to analyse the behaviour of MR fluid as well as to obtain the stiffness for varying magnetic field. MR damper mathematical model has been developed for evaluating dynamic response for experimentally obtained parameters. The experimental results show that the increase of applied electric current in the MR damper, the damping force will increase remarkably up to the saturation value of current. The numerical simulation results that stiffness of the MR damper can be varied with the current value and increase the damping forces with the reduced amplitude of excitation. Experimental and theoretical results of the MR damper characteristics demonstrate that the developed MR damper can be used for vibration isolation and suppression.

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