Magnetorheological Fluid Damper Research Articles

Prediction Model of Magnetorheological (MR) Fluid Damper Hysteresis Loop using Extreme Learning Machine Algorithm

Abstract Magnetorheological (MR) fluid is among the smart materials that can change its default properties with the influence of a magnetic field. Typical application of an MR fluid based device involves an adjustable damper which is commercially known as an MR fluid damper. It is used in vibration control as an isolator in vehicles and civil engineering applications. As part of the device development process, proper understanding of the device properties is essential for reliable device performance analysis. This study introduce an accurate and fast prediction model to analyse the dynamic characteristics of the MR fluid damper. This study proposes a new modelling technique called Extreme Learning Machine (ELM) to predict the dynamic behaviour of an MR fluid damper hysteresis loop. This technique was adopted to overcome the limitations of the existing models using Artificial Neural Networks (ANNs). The results indicate that the ELM is extremely faster than ANN, with the capability to produce high accuracy prediction performance. Here, the hysteresis loop, which represents the relationship of force-displacement for the MR fluid damper, was modelled and compared using three different activation functions, namely, sine, sigmoid and hard limit. Based on the results, it was found that the prediction performance of ELM model using the sigmoid activation functions produced highest accuracy, and the lowest Root Mean Square Error (RMSE).

Active damping of chatter in the boring process via variable gain sliding mode control of a magnetorheological damper

In this article, a sliding mode control of a magnetorheological fluid damper is presented for active damping of chatter in the boring process for the first time. A boring bar is integrated with an in-house developed magnetorheological fluid damper system. The variable gain super twisting sliding mode control algorithm is designed and implemented for suppressing the chatter in the boring process. Simulations of the controller show its fast response and robustness against disturbances and parametric uncertainties. Validation cutting tests performed under various machining conditions showed that the stability limit can be increased significantly with the sliding mode control of the magnetorheological fluid damper.

Reliability assessment and seismic control of irregular structures by magnetorheological fluid dampers

The catastrophic damages of past earthquakes show that irregular structures are more vulnerable to seismic excitation. On the other hand, dynamic responses depend on the severity of irregularity which is hard to be determined precisely. In this study, performance and reliability of magnetorheological (MR) fluid dampers in controlling torsional-lateral responses of irregular structures are evaluated. In this regard, plan-asymmetry is studied by considering mass eccentricity; whereas vertical-irregularity is investigated by creating mass difference in adjacent stories of the structure. The performance of MR dampers in seismic control of the structure is then evaluated for passive and semi-active control scenarios. The reliability of the structure-MR damper system is then studied by considering uncertainties in severity of irregularities using the Monte Carlo simulation method. Six types of limit state function are defined and the reliability of the system for controlling the desired responses are derived. The results show satisfactory performance of MR dampers in controlling coupled torsional-lateral responses of the structure in which semi-active control system outperforms the passive control system. The results also confirm that the performance of the control system highly depends on the structure irregularity which should be taken into account for design of a safe and reliable structure.

Reliability assessment of MR fluid dampers in passive and semi-active seismic control of structures

In this paper, the reliability assessment of magnetorheological (MR) dampers in reducing structures’ seismic responses is studied. Two passive and semi-active control scenarios are considered and discussed. For semi-active control scenario, the Lyapunov control algorithm is used. In order to minimize the structure’s responses under a given earthquake excitation, an unconstrained optimization problem is first defined and solved via genetic algorithm to find an optimal diagonal matrix in Lyapunov’s control algorithm. The procedure is explained for a three-storey benchmark shear structure equipped with MR damper in all storeys. The structure’s responses reliability for various uncertainties are derived and interpreted based on standard Monte Carlo simulation approach. In the reliability problem, for the limit state function two cases based on human comfort and structural safety criteria are defined and investigated. Furthermore, the most influential uncertain variables and control scenarios on structures’ reliability are identified. Finally, a sensitivity analysis on the coefficient of variations of random variables on the structure’s responses reliability is accomplished. The results show that in the joint event, the MR damper is more reliable for acceleration control rather than drift control in passive control scenario. The aforementioned trend is reversed for semi-active control scenario. Additionally, passive control scenario is more reliable than the semi-active control scenario in reducing maximum acceleration of structure. However, in reducing maximum drift of structure, the values of the reliability in semi-active control scenario are almost similar to passive control scenario.

Shear Mode Damper Testing Using Flake Shape Based Magnetorheological Fluids

Use of anisotropic iron particles in the magnetorheological (MR) fluid having a high yield stress is a challenge as it increases the viscosity of the fluid in off-state. In this clause, a novel flake shaped iron powder based MR fluid with high yield stress is synthesized and used in shear mode MR damper (SMMD). MR damper design is optimized using fluid properties and Bingham model. Damping performance of newly synthesized MR fluid damper is at par with the available friction based damper used in front loaded washing machine. The unique feature of this design is minimal volume of the fluid (1.5 ml) required to achieve damping force of 50N. Effect of different volume percentage of particles in MR fluid is evaluated in terms of damping force. Effect of testing parameters like displacement and frequency of excitation on damping force was evaluated. Effect of settling of particle on damper performance is discussed in this work. It shows that the flakes shaped-based MR fluid show better stability against gravity. The smaller quantity of present flake shaped-based MR fluid will reduce the cost of shear mode damper.

Semi-Active Scissors-Seat Suspension With Magneto-Rheological Damper

A cab seat suspension with a magneto-rheological (MR) fluid damper is introduced in this paper. A unified-format model for the MR damper is proposed to describe the dynamic characteristics of the MR damper. Also, a simple force-inverse model and a viscous damping tracking model are used for the coil current solution. A digital integrator and an extended Kalman filter are respectively adopted to obtain the vibration velocity of the chair frame and the relative motion velocity of the MR damper piston. A new skyhook control base with viscous damping tracking is applied to the semi-active seat suspension. In the simulation, compared with passive seat suspension under different displacement excitation (2, 4, 6, 8 Hz-sine, and random), the acceleration root mean square of the seat suspension with the MR damper is reduced by 52.2%, 32.2%, 41.3%, 50.8%, and 34.6%, respectively. In the experiment, the acceleration root mean square is reduced by 11.2%, 41.2%, 45.8%, and 31.5%, respectively under different displacement excitation (2, 4, 6, and 8 Hz-sine).

A Magneto-Thermo-Static Study of a Magneto-Rheological Fluid Damper: A Finite Element Analysis

Nowadays, the automotive industry is oriented toward the production of new generation devices, such as magnetorheological fluid (MR fluid) dampers, which have a proven simplicity of design combined with reduced maintenance. Being devices powered by steady-state electric current, MR fluid dampers develop steady-state magnetic induction fields with associated steady-state thermal stresses and a consequent constant yield stress. In this work, an asymmetric MR damper has been studied using the finite-element method (FEM). Specifically, since steady-state electric current circulates in the coil of the device, a magneto-static analysis of the device and particularly of the strip of MR fluid contained therein is performed using the FEM. Furthermore, as the device is subject to heating during operation, a thermo-static analysis was also carried out using finite elements when different external temperatures were considered. Both analyses, performed by ANSYS ToolbBox, highlighted the areas of the device most subject to magnetic stress providing useful indications on the influence of temperature both on the magnetization of the magnetic particles and on the MR fluid as a whole.

Modelling and validation of magneto-rheological fluid damper behaviour under impact loading using interpolated multiple adaptive neuro-fuzzy inference system

PurposeThe objective of this paper is to develop a fast modelling technique for predicting magneto-rheological fluid damper behaviour under impact loading applications.Design/methodology/approachThe adaptive neuro-fuzzy inference system (ANFIS) technique was adopted to predict the behaviour of a magneto-rheological fluid (MRF) damper through experimental characterisation data. In this study, an MRF damper manufactured by Lord Corporation was used for characterisation using an impact pendulum test rig. The experimental characterisation was carried out with various impact energies and constant input currents applied to the MRF damper.FindingsThis research provided a fast modelling technique with relatively less error in predicting MRF damper behaviour for the development of control strategies. Accordingly, the ANFIS model was able to predict MRF damper behaviour under impact loading and showed better performance than the modified Bouc–Wen model.Research limitations/implicationsThis study only focused on modelling technique for a single type of MRF damper used for impact loading applications. It is possible for other applications, such as cyclic loading, random loadings and system identification, to be studied in future experiments.Original/ValueFuture researchers could apply the ANFIS model as an actuator model for the development of control strategies and analyse the control performance. The model also can be replicated in other industries with minor modifications to suit different needs.

Development of multibody dynamical using MR damper based semi-active bio-inspired chaotic fruit fly and fuzzy logic hybrid suspension control for rail vehicle system

In this paper, the semi-active suspension in railway vehicles based on the controlled Magnetorheological (MR) fluid dampers is examined, and compared with the semi-active low and semi-active high suspension systems to enhance the running safety, ride quality and ride comfort for a high-speed rail vehicle. Fuzzy logic and chaotic fruit fly control techniques are used as system controllers to determine desired damping forces for front and rear bogie frame with force track-ability of system controllers. A 28 degrees of freedom (DoF) mathematical model of the rail vehicle is formulated using nonlinear vehicle suspension and nonlinear heuristic creep model. The Modified Dahl model is formulated to characterize the behavior of the MR damper. The simulation result is validated using the experimental results. Four different suspension strategies are proposed with MR damper i.e. passive, semi-active low, semi-active high and semi-active intelligent compound controller based on bio-inspired chaotic fruit and fuzzy logic hybrid controller. A comparison indicates that the semi-active controller gives the optimum performance based on frequency and time response analysis for comfort vibration actuation (9.088 to 15.33%), ride quality (14.81–20.73%) and comfort (24.91–27.81%) and it has little influence on derailment quotients, offload factors, as a result, it will not endanger the running safety of rail vehicle.

Design and Development of Smart Semi Active Suspension for Nonlinear Rail Vehicle Vibration Reduction

In this paper, the semi-active suspension in railway vehicles based on the controlled magnetorheological (MR) fluid dampers is examined, and compared with the semi-active low and semi-active high suspension systems to enhance the running safety and ride quality for a high-speed rail vehicle. Predictive model controllers are used as system controllers to determine the desired damping forces for front and rear bogie frame with force track-ability. A 28 degree of freedom (DoF) mathematical model of the rail vehicle is formulated using nonlinear vehicle suspension and nonlinear heuristic creep model. The MR model of Ali and Ramaswamy is formulated to characterize the behavior of the MR damper. The simulation result is validated using the experimental results. Four different suspension strategies are proposed with MR damper, i.e. passive, semi-active low, semi-active high and semi-active smart controller based on predictive model controller. A comparison indicates that the semi-active controller gives the optimum for comfort vibration actuation and improves the ride quality and it has little influence on derailment quotients, offload factors, as a result, it will not endanger the running safety of rail vehicle.

Identifying Stochastic Frequency Response Functions Using Real-Time Hybrid Substructuring, Principal Component Analysis, and Kriging Metamodeling

Real-time hybrid substructuring (RTHS) has previously been shown to be an effective tool to quantify the effect of parametric uncertainties on the response of a structural system. Proposed and implemented in this paper is a method that combines RTHS, Principal Component Analysis, and Kriging to metamodel the frequency response functions of a structure. The proposed method can be used to account for parametric variation in both the numerical and physical substructures. This approach is demonstrated using a series of bench-scale RTHS tests of a magnetorheological (MR) fluid damper used to control a 2 degree-of-freedom mass-spring system. The numerical system spring stiffnesses and the physical current supplied to the MR damper are each treated as uniformly distributed random variables. The RTHS test data is used to train computationally fast metamodels, which can then be used to conduct Monte Carlo simulations to determine distributions of the system response. The proposed methodology is shown to be both efficient and accurate.

Parameter identification of Bouc-Wen model for Magnetorheological (MR) fluid Damper by a Novel Genetic Algorithm

In this research, novel genetic algorithm (nGA) is proposed for Bouc-Wen modle parameters esstimation for magnetorheological (MR) fluid dampers. The optimization efficiency is improved by modifying the crossover and mutation steps of a GA. In the crossover stage, the probability of reproducing offspring from the same parent (same mother and father chromosome) is done to be zero, which may happen in the standard GA, and the probability of a chromosome to be selected for mating is based on error rank weighting of the chromosomes. Additional fitness evaluation of chromosomes will take place in between the crossover and mutation steps to save the best chromosome found so far, which is not implemented in the standard genetic algorithm (GA). The model is validated by comparing its simulation output force ( Fsim) with experimentally generated MR damper force ( Fexp). The mean absolute error, standard deviation and number of generations for convergence are taken as a criterias for performance evaluation. With these ctriterias, the proposed novel GA outperform better than the other researches. The accuracy is improved by 46.67% compared to standard GA. The proposed novel GA for Bouc-Wen model parameter identification can be used for any MR damper control system with better accuracy.

Design and geometric parameter optimization of hybrid magnetorheological fluid damper

A hybrid type magneto-rheological (MR) fluid damper based on electromagnet and two permanent magnets apart from electromagnet was designed and its characteristics were analyzed numerically. In the proposed MR damper, the magnetic field is generated by the permanent magnet and raised by the additional electromagnet. This combination provides a larger amount of damping force with lower consumption of electric energy. The proposed model has an additional advantage of providing a moderate damping force in case of electromagnet failure. The magnetic circuit of a hybrid MR valve was analyzed by applying Kirchhoff’s law and magnetic flux conservation rule. A 2D axisymmetric model of the proposed hybrid MR damper was developed in commercial software where magnetic field properties are analyzed by finite element method. The optimization process was developed to optimize the geometric parameters and generated damping force using design of experiment (DoE) technique. The damping force of the MR damper was selected as an objective function. The optimal solution to the optimization problem of the hybrid MR valve structure was evaluated and compared with the solution obtained from the initial parameters. It is demonstrated that the novel hybrid type provides higher damping force than the previous model.

Design and experiment of a new structure of MR damper for improving and self-monitoring the sedimentation stability of MR fluid

Magnetorheological (MR) fluid damper is a high quality semi-active vibration damping device based on magnetorheological effect. However, one of the key factors restricting its development and application is the sedimentation of magnetic particles in MR fluids at present, which affects the working stability and service life of the damper, while there is a lack of effective method for monitoring sedimentation state of MR fluid inside the device in real time. A new structure of MR fluid damper for improving and monitoring the sedimentation stability of MR fluid is developed in this study based on the sedimentation principle and work characteristics of MR damper. Firstly, the theoretical analysis of the new MR fluid damper is carried out, then the prototype is designed and processed, the appropriate MR fluid is selected, finally the performance of the prototype is tested. The results of experiment show that the force of the new damper can be adjusted in both directions, and the output force can meet the requirements of working conditions. The resistance of MR fluid decreases and the conductivity of MR fluid increases in the middle of the damping channel, and the partial voltage at both ends of the non-inductive resistance increases gradually, which verifies the feasibility of the monitoring device for sedimentation. The voltage at both ends of the non-inductive resistance decreases slightly after placement for 24 weeks, so it can be judged that the sedimentation of MR fluid is weak in the new MR damper, which verifies the effectiveness of the new structure for improving sedimentation stability.

Application of the Taguchi method for finite element analysis of a shear-type magnetorheological fluid damper

A magnetorheological fluid damper is a device in which a magnetorheological fluid is filled in a damper. In this device, the magnetic field is controlled by an external current (voltage) so that the magnetic force of a piston inside the damper changes like an electromagnet. The damping force of the damper is controlled by changing the magnetic force of the piston. With the increasing magnetic force of the piston, the viscosity of the magnetorheological fluid in the damper increases. The primary aim of this study was to maximize the magnetic flux density and identify the following influencing factors from the relevant literature: piston and outer tube materials, piston length, piston diameter, cylinder wall thickness, damper channel clearance, gap channel length, current, and magnetorheological fluid. A magnetic circuit analysis was performed using ANSYS Maxwell, and the optimal parameter combination was identified using the Taguchi method. The analysis of variance was used to examine the influence of various factors on quality characteristics. This study helps understand the relation between structure size, material, and magnetic flux density and contributes to future generations of magnetorheological fluid damper design analysis.

Mechanical performance of a novel magnetorheological fluid damper based on squeeze-valve bi-mode of MRF

In this paper, a novel magnetorheological (MR) damper working in the squeeze-valve bi-mode of MR fluid (MRF) was developed. The damper was consisted of two parts: the valve part and the squeeze part. Both of the two working parts could provide damping force when the damper worked. Firstly, the model of the novel damper was established to ensure that the damper structure was suitable for our design. Then, the magnetic field distribution inside the MR damper was simulated. The simulated results showed that the magnetic flux density was 120 mT when the current in the coil was 2.0 A, and the magnetic field distribution was uniform at the working area of the MRF. The magnetic flux density inside the damper could be controlled by changing the current in the coil. Finally, the damper was fabricated and its mechanical properties were tested by the universal testing machine (MTS 809). The influences of the displacement, frequency, current, and velocity on the damping force were systematically analyzed. The test results indicated that the largest damping force provided by the MR damper was about 6.5 kN. The curves of the damping force versus displacement were plump, which indicated that the ability of the damper to expend energy was well. The effective damping increased from 31.5 to 620 kNs m−1 when the current increased from 0 to 2 A. The results indicated the properties of the damper could change in a huge range. To analyze the semi-active control performance of the damper, the back propagation neural network was trained to predict the damping force. The predicted results matched well with the experimental results, which indicated that this novel MR damper had great potential in the semi-active control field.

Design optimization and experimental characterization of a rotary magneto-rheological fluid damper to control torsional vibration

This paper aims at optimum design formulation of a rotary disk-type magneto-rheological (MR) fluid damper to increase its torsional vibration control performance. The objective is to maximize the torsional damping torque for a given volume, geometric and inertia constraints. The damping torque has been derived based on Bingham plastic model for a commercial MR fluid provided by Lord corporation. As MR fluid’s yield strength directly depends on the applied magnetic field intensity, an analytical magnetic circuit analysis has been conducted to approximately evaluate the magnetic field intensity in the MR fluid gap. A finite element model of the rotary MR damper has also been developed to evaluate the magnetic field distribution. A formal design optimization problem has then been formulated to maximize the dynamic range for a given volume under geometric, inertia and torque ratio constraints. Genetic algorithm combined with sequential quadratic programming method has been utilized to accurately capture the global optimum solution. Finally, a proof-of-concept of the optimal design has been manufactured and then tested experimentally to investigate the generated damping torque under different current excitation and also to validate the model and optimization strategy.

Damping Force Analysis and Optimization of a Lunar Lander with MRF

AbstractControllable lunar landers with magnetorheological fluid (MRF) damper have become a hot topic of research. However, limited research studies have been performed on the damping force analysi...

Design and experimental study of the porous foam metal magnetorheological fluid damper based on built-in multi-pole magnetic core

The porous foam metal magnetorheological fluid damper has a broad application prospect in the field of vibration isolation of precision instruments with small damping force because it does not need complex dynamic seal structure. The traditional single-ring magnetic pole porous foam metal magnetorheological fluid damper has a small effective area for the magnetic core that affects the damper output range due to the geometric constraints of the coil and the low magnetic field utilization. Therefore, in order to increase the effective area ratio of the magnetic core, this article introduces the built-in multi-pole magnetic core into the porous metal magnetorheological fluid damper and integrates four axial wound fan-shaped magnetic poles on the magnetic core to improve the output performance of the damper. The magnetic circuit is analyzed based on Ohm’s law of magnetic circuit, and the mathematical model of damping force is established. Based on this, the important geometric parameters of the damper are determined. The finite element method is used to simulate the magnetic field of the damper, and the output performance of the damper is numerically simulated. The dynamic performance test system of the damper is set up to test the designed damper, and the test data and numerical simulation results are verified with each other. The results show that the damping force peak and dynamic regulation range of the damper designed in this article are higher than those of the traditional porous foam metal magnetorheological fluid damper with magnetic core, which effectively improves the mechanical properties of the magnetorheological fluid damper with porous foam metal.

Improvement of chatter stability in boring operations with semi active magneto-rheological fluid damper

Boring is a machining process, which is used to enhance the size of a pre drilled hole. In boring operation the tool vibration is an unmanageable part of the machining process. This affects the tool life and surface finish of the workpiece. When the magneto rheological fluid subjected to an external magnetic field, which changes the stiffness and undergoes a phase transformation. The stiffness and energy dissipation properties of the MR fluid controlled boring bar can be adjusted by varying the strength of the applied magnetic field. In this paper, semi active radially arranged magneto rheological fluid dampers were adopted to suppress the boring bar vibration. Experiments were conducted for different spindle speeds with the HSS boring bar tool on a mild steel workpiece. Vibrational characteristics based on surface roughness and chatter reduction were studied. The experimental result shows that, tool chatter was reduced ineffectiveness with the use of radial arrangement of dampers.