Magnetorheological Fluid Mount Research Articles

New bell plate controlled multi-inertia channel magnetorheological fluid mount wide frequency vibration isolation control study

This paper introduces a novel type of magnetorheological fluid (MRF) mount designed to achieve wide-frequency vibration isolation for engines. While previous studies have explored vibration isolation using hydraulic mounts, there has been limited research on achieving wideband isolation with MRF mounts. Consequently, this paper presents an innovative MRF mount structure and investigates wideband vibration isolation control for engines. Initially, experiments with a multi-channel MRF damper validate the switchable operation of controllable channels. A novel controllable multi-inertia channel MRF mount system is proposed, aligning the working mode of controllable inertia channels with that of the MRF damper. The lumped parameter method is employed to derive the mathematical model of the MRF mount, and its high and low-frequency dynamic characteristics are thoroughly examined. Subsequently, a real-time multi-island genetic algorithm-optimized controller is developed to investigate wideband vibration isolation within the MRF mount system. The findings indicate that: (1) The MRF mount demonstrates adjustable low-frequency dynamic stiffness and loss angle within the frequency range of f = 0–50 Hz. In the frequency range of f = 50–100 Hz, the mount achieves its lowest dynamic stiffness value, effectively addressing the issue of high-frequency stiffening. (2) The real-time multi-island genetic optimized controller exhibits superior vibration isolation performance compared to traditional sky-hook control and hybrid sky-hook control methods, achieving optimal vibration isolation for the mount.

Multi-Objective Optimization of Magnetorheological Mount Considering Optimal Damping Force and Maximum Adjustable Coefficient

To address the problem of multiple working conditions and complex requirements in magnetorheological fluid (MRF) mounts, a high-precision damping characteristic optimization method is explored. Based on the parallel plate model, the equation of fluid motion in the inertial channel was established according to the Navier–Stokes equation, and the MRF mount damping characteristics were analyzed. Considering the fluid model to be suitable in the steady-state, the model was experimentally verified, and the extended equation was fitted. Multi-objective optimization design was carried out by considering the large damping force and adjustable coefficient as the optimization goal and external geometric dimensions as variables. According to results, under the radial-channel MRF mount structure, the magnet core depth has the least influence on the damping force; furthermore, the damping performance can be quickly improved by changing the height of the inertial channel. The addition of the extended equations further improved the accuracy of the fluid model. The multi-objective optimization design can improve the strength and uniformity of the flux density of the MRF mount damping gap. After optimization, the damping force is increased by 44.64%; moreover, when the current is increased from 1.5 to 1.8 A, the controllable force increases by only 2.26%, and the damping performance is fully exerted.

Dynamic characterization of controlled multi-channel semi-active magnetorheological fluid 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.

A heavy-duty magnetorheological fluid mount with flow and squeeze model

In this paper, a new type of heavy-duty magnetorheological fluid (MRF) mount is proposed and experimentally investigated. The MRF mount with both annular and radial channels are based on two operating modes: flow mode and squeeze mode. The combined paths can lengthen the MRF valve and hence maximize the MR effect in flow mode. A mechanical model is established to institutively predict the maximum damping force that the device can achieve. Magnetic field distribution of the MRF mount is then evaluated based on finite element analysis. Both squeeze and flow regions can obtain magnetic field intensities up to 0.742 T and 0.7 T under 1 A current, respectively. Finally, the quasi-static and dynamic tests of MRF mount under different loading conditions (frequency, amplitude, current) are performed and the results showed that the proposed MRF mount can provide large damping force up to 18.843 kN and wide tunable range (719% increase on damping force at 0.1 Hz with 2 mm amplitude).

A magneto-rheological fluid mount featuring squeeze mode: analysis and testing

This paper presents a mathematical model for a new semi-active vehicle engine mount utilizing magneto-rheological (MR) fluids in squeeze mode (MR mount in short) and validates the model by comparing analysis results with experimental tests. The proposed MR mount is mainly comprised of a frame for installation, a main rubber, a squeeze plate and a bobbin for coil winding. When the magnetic fields on, MR effect occurs in the upper gap between the squeeze plate and the bobbin, and the dynamic stiffness can be controlled by tuning the applied currents. Employing Bingham model and flow properties between parallel plates of MR fluids, a mathematical model for the squeeze type of MR mount is formulated with consideration of the fluid inertia, MR effect and hysteresis property. The field-dependent dynamic stiffness of the MR mount is then analyzed using the established mathematical model. Subsequently, in order to validate the mathematical model, an appropriate size of MR mount is fabricated and tested. The field-dependent force and dynamic stiffness of the proposed MR mount are evaluated and compared between the model and experimental tests in both time and frequency domains to verify the model efficiency. In addition, it is shown that both the damping property and the stiffness property of the proposed MR mount can be simultaneously controlled.

Quasi-steady modelling for magneto-rheological fluid mount based on squeeze mode and experimental testing

A Magneto-rheological (MR) fluid mount based on parallel disk squeeze mode, is put forward to implement the controllable dissipation of vibration energy. An analytical quasi-steady modelling is proposed to simulate the MR fluid squeeze radial flow. Its differential equation is set and solved with the Navier slip boundary condition and the compatible condition. Both the MR fluid radial flow velocity profile and the radial pressure distribution are derived by using bi-viscous constitutive model. The interface between the Newtonian flow region and bi-viscous flow region is theoretically determined. An approximate arithmetic of the squeeze force is developed and its mathematical expression is obtained. Some influences of the slip coefficient and the radial coordinate on the radial flow velocity profile are examined. To verify the modelling, a corresponding MR fluid mount is designed and fabricated and tested on MTS870 Electro-hydraulic Servo using sine wave excitation (oscillation frequency 5 Hz, amplitude 1.0 mm, current from 0.0 to 2.0 A in increments of 0.2 A). The experimental result reveals that the analytical squeeze result is in good agreement with the experimental squeeze forces. The diagram of the analytical squeeze forces vs. disk displacement agrees mainly with that from the experimental testing.

Hydraulic hybrid vehicle vibration isolation control with magnetorheological fluid mounts

Hydraulic Hybrid Vehicle (HHV) is an emerging technology especially for heavy-duty vehicles, thanks to its high efficiency and power density. However, one of the main problems that should be solved to enable the successful commercialisation of HHV is the excessive noise and vibration involved with hydraulic systems. This study focuses on using the magnetorheological fluid (MRF) technology to reduce the noise and vibration transmissibility from the power sources to the vehicle body. To study the noise and vibration of HHVs, a HHV structure in parallel design was analysed. An MRF mount, to use for the engine and pump/motor, was designed, fabricated and tested. Vibration control schemes based on the skyhook algorithm were utilised to reduce the transmissibility and amplitudes of vibration. The research showed that the MRF mounts played an important role in reducing the noise and vibration transmitted to the vehicle body. Additionally, the locations and orientations of the isolation system affected the efficiency of the noise and vibration mitigation.

Engine Isolation Control via Magnetorheological Technology

The mount with variable damping and stifsfnes characteristics is very important for engine active isolation in whole frequency region. Based on building one engine isolation dynamic model with three degree of freedom, a magnetorheological (MR) parallel-mount system is proposed, which includes one MR damper with variable damping and one MR elastomer with variable stiffness. To decrease vertical force and cross moment transmitted from engine to base, a fuzzy adaptive controller is designed for vertical isolation, which can online adjust quantization factors and scale factor by human-simulation intelligent parameter modifying algorithm. And coordination control strategies are given to adjust damping and stiffness of each MR parallel-mount. Then the simulation isolation system of engine is developed in Matlab and the test-bed isolation system of engine is built in the laboratory. With wide frequency input, studies on different engine mount isolation are carried out. Simulation results indicate that MR parallel-mount has distinct advantages compared to other mounts. Laboratory results show that compared to rubber mount and hydraulic mount, MR fluid mount reduces absolute transfer coefficient of force and moment to less than 30 percents in a broader frequency region, which is very useful to enhance the ride comfort.

Vibration Control of a Structural System Using Magneto-Rheological Fluid Mount

In this work, a mixed mode-type magneto-rheological fluid mount (MR mount in short) is devised by considering the nondimensional formulation of Bingham plastic flow, and applied to vibration control of a structural system subjected to external excitations. The structural system consists of a vibrating mass, semi-active MR fluid mount, and passive rubber mounts. The MR mount is installed on the beam structure as a semi-active actuator and supports the vibrating mass, while the flexible beam structure is supported by two passive rubber mounts. After verifying the field-dependent damping force characteristics of the MR mount, the governing equation of the structural system is derived in the modal coordinate and rewritten as a state space control model. The linear quadratic Gaussian (LQG) controller is then formulated in order to attenuate vibration of the structural system. The LQG controller is experimentally realized and control responses such as accelerations and transmitted forces of the structural system are presented in the frequency domain.