Flow Mode Magnetorheological Dampers Research Articles

Design and experimental evaluation of a novel flow-mode magnetorheological damper without accumulator

Researchers in the field of vibration control have shown increasing interest in magneto-rheological dampers (MRDs) in recent years. Conventional flow-mode MRDs typically employ a gas chamber as an accumulator to accommodate volume changes and promote fluid communication. However, this approach introduces manufacturing complexities and raises production costs. To overcome these challenges, we propose a novel configuration for flow-mode MRDs that replaces the accumulator with a structural constraint. This modification leads to a more compact and cost-effective MRD solution suitable for engineering applications. This paper presents an introduction, followed by the configuration and design of the novel MRD for a case study involving a vehicle suspension system. To enhance output performance, we optimize the significant geometry of the damper using the finite element method (FEM), taking into account the damping force, off-state force, and inductive time constant of the damper. Based on the optimal simulation results, we provide a detailed design of the optimized flow-mode MRD without an accumulator for prototype fabrication. To assess the practical performance of the proposed MRD prototype, we conducted experiments on a test rig and engaged in comprehensive discussions based on the obtained results.

Study on the integrated structure/control design method of magnetorheological damper for improving vehicle posture

In order to achieve a good match between magnetorheological (MR) damper and vehicle Noise Vibration and Harshness (NVH) quality and improve vehicle posture while driving, an integrated design method of MR damper structure/control for vehicle vibration suppression was proposed considering the coupling effect between MR damper structure parameters and controller parameters. A controller was designed to control the damping force generated by the tapered channel MR damper. Furthermore, the damping force expression of the tapered flow mode MR damper was derived, and the damping force was introduced into the vehicle dynamics model. In order to improve the vehicle posture, an integrated structure/control platform combining response surface model, current controller and vehicle dynamics model was established. Based on integrated platform, the vehicle dynamics model and Fourier transform were adopted to extract the time-frequency characteristics of the design objective under different working conditions. In the optimization process, the damper structure was optimized by taking the time domain values as the constraints and the frequency domain values as the optimization goals. The results show that the proposed integrated design method of MR damper can obtain its global optimal structural parameters under different driving conditions. The acceleration root mean square (RMS) values and frequency domain values of vehicle were both reduced to varying degrees, achieving the purpose of improving the vehicle posture.

Characterization of magneto-rheological fluid having elongated ferrous particles and its implementation in MR damper for three-wheeler passenger vehicle

In the present research work, Magneto-rheological (MR) fluid consisting of fiber-like elongated carbonyl ferrous particles as dispersed phase is characterized and the dynamic performance of the three-wheeled vehicle with an (MR) damper has been analyzed and discussed. Broadly, this paper has two segments, in the first segment, different proportions of MR fluid, that is, 10%, 15%, and 20% of volume fraction, are prepared and the corresponding rheological behaviors are studied experimentally at different current levels. In the second segment, the experimentally obtained properties of MR fluids are used to estimate the dynamic force of MR damper by using a non-parametric model of the flow-mode MR damper. Mathematical modeling of three-wheeler vehicle having MR damper model with proportional–integral–derivative (PID) control has been developed and the ride comfort and stability performances under poor road condition are studied. The result shows that the three-wheeler passenger vehicle equipped with an MR damper-based suspension system provides better ride comfort and stability with 27.6% reduction in bounce, 81.8% reduction in pitch, and 27.6% reduction in the roll motion of the body when compared to its passive suspension counterpart.

The effect of mesocarbon microbeads on magnetorheological fluid behavior

Magnetorheological (MR) fluids are composed of magnetizeable particles suspended in a carrier fluid and change apparent viscosity upon the application of a magnetic field. Previous studies have shown that passive particles, such as hollow glass spheres, can augment the yield stress of MR fluids, but this yield stress augmentation has limited endurance because the hollow glass microspheres are not sufficiently durable. This study evaluates mesocarbon microbeads (MCMBs) as an alternative passive particle with the potential for MR yield force augmentation but with greater durability. The yield properties of six MR fluid concentrations with varying carbonyl iron particle (CIP) and MCMB volume fractions were tested using a shear mode rheometer and flow mode MR damper. MCMBs did not augment yield stress in shear mode, but, in contrast, in flow mode, the yield force increased nonlinearly with MCMB volume fraction. Furthermore, this yield force-enhancing effect did not diminish over 100,000 cycles (or 5 km of piston travel). The theoretical non-dimensional plug thickness which arises from an approximate parallel plate analysis of a fluid element in flow mode is used illustrate to a potential mechanism for the yield force augmentation effect.

Design and multi-objective optimization of magnetorheological damper considering vehicle riding comfort and operation stability

Mostly, magnetorheological (MR) dampers were optimized based on individual performance, without considering the influence of structure parameters change on vehicle performance. Therefore, a multi-objective optimization scheme of MR damper based on vehicle dynamics model was proposed. The finite element method was used to analyze magnetic flux density distribution in tapered damping channel under different structure parameters. Furthermore, the damping force expression of the tapered flow mode MR damper was derived, and the damping force was introduced into the vehicle dynamics model. In order to improve the ride comfort and operation stability of the vehicle, a collaborative optimization platform combining magnetic circuit finite element analysis and vehicle dynamics model was established. Based on this platform, the optimal design variables were determined by comfort and stability sensitivity analysis. The time domain optimization objective and frequency domain optimization objective are proposed simultaneously to overcome the lack of time domain optimization objective. The results show that compared with the time domain optimization and the initial design, the suspension dynamic deflection, tire dynamic load and vehicle body vertical acceleration are decreased after the time-frequency optimization. At the same time, in the frequency domain, the amplitude of vibration acceleration in each working condition is significantly reduced.

Dual Hysteresis Model of MR Dampers

This study concerns modeling the hysteretic behaviour of magnetorheological (MR) dampers. In general, hysteresis is one of key factors influencing the output of such actuators. So far more attention of various researchers has been paid to studying the combined hysteretic behaviour of MR actuators by observing the relationships between the output (force/torque) and the inputs (current, velocity, position). However, these devices feature two distinct hysteretic mechanisms: mechanical/hydraulic and magnetic. The mechanical hysteresis is of different nature than the magnetic hysteresis due to the properties of ferromagnetic materials forming the actuator's elec- tromagnet circuit, and these should be split in the modeling process. In the present study we separate the magnetic hysteresis from the mechanical/hydraulic one by investigating the magnetic flux vs exciting current relationship of a commercial flow-mode MR damper subjected to sinusoidal current loading and independently of the mechanical excitations. The resulting behaviour of the electromagnetic circuit is then examined using the nonlinear inductor approach with hysteresis. Total hysteresis is then modeled using a non-linear inductor model in combination with a phenomenological parametric Maxwell type model of the damper.

Design Optimization of Flow Mode Magnetorheological Damper

To control the vibrations with passive suspension system having limitation with constant damping force. By using smart material like magnetorheological fluid, it is possible to control the damping performance of suspension system using current variations in magnetic coil. Applications of this kind of damper are in front loaded washing machine and damper use in driver seat of heavy duty vehicles. Mainly flow mode MR damper is most commonly used damper for these two applications. This paper represents theoretical model and optimized design of flow mode MR damper. For any kind of MR damper design of magnetic coil is play very vital role. So for this paper mainly includes the design of coil and different parameters like number of coil distance between two coil current passing from the coil is consider for design and optimization using FEMM software. This work also includes the theoretical study of MR damper characteristics with force-displacement and force velocity plot with change in piston diameter and fluid gap.

Optimal design and performance evaluation of a flow-mode MR damper for front-loaded washing machines

It is well known that the vibration of washing machines is a challenging issue to be considered. This research work focuses on the optimal design of a flow-mode magneto-rheological (MR) damper that can replace the conventional passive damper for a washing machine. Firstly, rigid mode vibration of the washing machine due to an unbalanced mass is analyzed and an optimal positioning of the suppression system for the washing machine is considered. An MR damper configuration for the washer is then proposed considering available space for the system. The damping force of the MR damper is derived based on the Bingham rheological behavior of the MR fluid. An optimal design problem for the proposed MR brake is then constructed. The optimization is to minimize the damping coefficient of the MR damper while the maximum value of the damping force is kept being greater than a required value. An optimization procedure based on finite element analysis integrated with an optimization tool is employed to obtain optimal geometric dimensions of the MR damper. The optimal solution of the MR damper is then presented with remarkable discussions on its performance. The results are then validated by experimental works. Finally, conclusions on the research work are given and future works for development of the research is figured out.

Flow Mode Magnetorheological Dampers with an Eccentric Gap

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).

Hybrid magnetorheological fluid–elastomeric lag dampers for helicopter stabilityaugmentation

A laboratory demonstration of a hybrid magnetorheological fluid–elastomeric (MRFE)damper is investigated for adjustable or programmable lag mode damping in helicopters, sothat damping requirements can be varied as a function of different flight conditions. Thelaboratory demonstration of this hybrid MRFE lag damper consists of a double lap shearelastomeric damper in parallel with two magnetorheological (MR) flow mode dampers.This is compared to a damper where only elastomeric materials are implemented,i.e., a double lap shear specimen. The relationship between the output force andthe quasi-steady harmonic displacement input to a flow mode MR damper isexploited, where the output force can be adjusted as a function of applied magneticfield. Equivalent viscous damping is used to compare the damping characteristicsof the hybrid damper to a conventional elastomeric damper under steady-statesinusoidal displacement excitation. To demonstrate feasibility, a hybrid MRFEdamper test setup is designed, and single frequency (lag frequency or rotor in-planebending frequency) and dual frequency (lag frequency and rotor frequency) tests areconducted under different magnetic fields. The hybrid MRFE damper exhibitsamplitude-dependent damping behavior. However, with application of a magneticfield, the damping level is controlled to a specific damping level objective as afunction of displacement amplitude. Similarly, under dual frequency conditions,damping degradation at the lag frequency, because of lag motion at the rotorfrequency, can also be recovered by increasing magnetic field. A time-domainanalysis is developed to study the nonlinear dynamic behavior of the hybrid MRFEdamper. Using rate-dependent elasto-slides, the amplitude-dependent behavior ofthe hybrid MRFE damper is accurately reconstructed using both constant andcurrent-dependent (i.e. controllable) parameters. The analysis is physically motivated andcan be applied to the elastomer and MR fluid damper components separately.

A Magnetorheological Damper with Bifold Valves for Shock and Vibration Mitigation

This study presents the design and fabrication of a flow-mode bifold magnetorheological (MR) damper for shock and vibration mitigation for high piston velocity (15 mph or 6.75 m/s) as well as an evaluation of its performance at low speed. Based on a Bingham-plastic (BP) model, as well as a BP model coupled with a low speed hysteresis model, two theoretical MR damper models for flow-mode MR dampers are constructed. Using the design strategy associated with the Bingham-model based damper model, two MR damper designs for achieving the performance requirement with a limited space are considered: first, the conventional MR damper that has an MR valve inside the piston head and second, the bifold MR damper that has MR valves at each end of the damper. After numerically comparing the damping performances of the two MR damper designs, the bifold MR damper has been chosen because its dynamic range is better at high speed. The bifold MR damper was tested at a relatively low piston velocity using an MTS testing machine under sinusoidal loading. Experimental data compare well with the results predicted by the theoretical models.

Analysis and Testing of Electrorheological Bypass Dampers

We experimentally validate nonlinear quasi-steady electrorheological (ER) and magnetorheological (MR) damper models, using an idealized Bingham plastic shear flow mechanism, for the flow mode of damper operation. An electrorheological valve or bypass damper was designed, and fabricated using predominantly commercial off-the-shelf hydraulic components. Both the hydraulic cylinder and the bypass duct have cylindrical geometry, and damping forces are developed in the annular bypass via Poiseuille (flow mode) flow. Damper models assume parallel plate geometry. Three nondimensional groups are used for damper analysis, namely, the Bingham number, Bi, the nondimensional plug thickness, 6, and the area coefficient defined as the ratio of the piston head area, AP, to the cross-sectional area of the annular bypass, Ad. In the flow mode case, the damping coefficient, which is defined as the ratio of equivalent viscous damping of the Bingham plastic material, Ceq, to the Newtonian viscous damping, C, is a function only of the nondimensional plug thickness. The damper was tested using a mechanical damper dynamometer for sinusoidal stroke of 2 in., over a range of frequencies below 0.63 Hz. The damping coefficient vs. nondimensional plug thickness diagram was experimentally validated using these data over a range of damper shaft velocities or frequencies and applied electric fields. Because the behavior of ER and MR fluids are qualitatively similar, these ER damper modeling results can be extended to analysis of flow mode MR dampers.

Analysis and Testing of Electrorheological Bypass Dampers

We experimentally validate nonlinear quasi-steady electrorheological (ER) and magnetorheological (MR) damper models, using an idealized Bingham plastic shear flow mechanism, for the flow mode of damper operation. An electrorheological valve or bypass damper was designed, and fabricated using predominantly commercial off-the-shelf hydraulic components. Both the hydraulic cylinder and the bypass duct have cylindrical geometry, and damping forces are developed in the annular bypass via Poiseuille (flow mode) flow. Damper models assume parallel plate geometry. Three nondimensional groups are used for damper analysis, namely, the Bingham number, Bi, the nondimensional plug thickness, 6, and the area coefficient defined as the ratio of the piston head area, AP, to the cross-sectional area of the annular bypass, Ad. In the flow mode case, the damping coefficient, which is defined as the ratio of equivalent viscous damping of the Bingham plastic material, Ceq, to the Newtonian viscous damping, C, is a function only of the nondimensional plug thickness. The damper was tested using a mechanical damper dynamometer for sinusoidal stroke of 2 in., over a range of frequencies below 0.63 Hz. The damping coefficient vs. nondimensional plug thickness diagram was experimentally validated using these data over a range of damper shaft velocities or frequencies and applied electric fields. Because the behavior of ER and MR fluids are qualitatively similar, these ER damper modeling results can be extended to analysis of flow mode MR dampers.