Fitrian Imaduddin

Design and performance analysis of a compact magnetorheological valve with multiple annular and radial gaps

A novel concept of a compact magnetorheological valve is proposed based on the advance characteristics of magnetorheological fluid. The structural design consists of a meandering pattern formed by multiple annular and radial gaps in order to extend the flow path length of magnetorheological fluid. Extending the flow path of magnetorheological fluid is important in order to increase the density of effective area, so that the rheological properties of magnetorheological fluid can be widely regulated in a small size magnetorheological valve. The main objective of this article is to show that the pressure drop as one of the key performance indicators in a magnetorheological valve can be significantly increased using multiple annular and radial gaps configuration. In order to demonstrate the magnetorheological valve performance, simulation work using magnetic simulation software called finite element method–based software for magnetic simulation is conducted and combined with the pressure drop calculation using the derived magnetorheological valve model. Simulation results show that the magnetorheological valve with multiple annular and radial gaps is able to improve the achievable pressure drop. The discussion on the effect of gap size variations on the achievable pressure drop and the operational range of magnetorheological valve is also presented.

A review of design and modeling of magnetorheological valve

Following recent rapid development of researches in utilizing Magnetorheological (MR) fluid, a smart material that can be magnetically controlled to change its apparent viscosity instantaneously, a lot of applications have been established to exploit the benefits and advantages of using the MR fluid. One of the most important applications for MR fluid in devices is the MR valve, where it uses the popular flow or valve mode among the available working modes for MR fluid. As such, MR valve is widely applied in a lot of hydraulic actuation and vibration reduction devices, among them are dampers, actuators and shock absorbers. This paper presents a review on MR valve, discusses on several design configurations and the mathematical modeling for the MR valve. Therefore, this review paper classifies the MR valve based on the coil configuration and geometrical arrangement of the valve, and focusing on four different mathematical models for MR valve: Bingham plastic, Herschel–Bulkley, bi-viscous and Herschel–Bulkley with pre-yield viscosity (HBPV) models for calculating yield stress and pressure drop in the MR valve. Design challenges and opportunities for application of MR fluid and MR valve are also highlighted in this review. Hopefully, this review paper can provide basic knowledge on design and modeling of MR valve, complementing other reviews on MR fluid, its applications and technologies.

A high performance magnetorheological valve with a meandering flow path

The huge developments in the field of magnetorheological (MR) fluid-based devices will have a great influence on the future of mechatronic applications due to the ease of interfacing between electronic controls and the mechanical components that they provide. Among various MR fluid-based devices, an MR valve would be particularly significant for the development of other devices, if it could be successfully achieved. One of the most challenging obstacles to MR valve development is the difficulty of achieving device miniaturization while, at the same time, improving the achievable performance. This study demonstrates a novel design for an MR valve, using the meandering flow path approach in order to increase the effective area so that the MR fluid can be regulated within a small-sized valve. The meandering flow path is formed by combining multiple annular, radial and orifice flow channels. In order to analyze the valve performance, a mathematical model of the proposed MR valve is derived and combined with numerical simulation using the finite element method, with the intention of predicting the achievable pressure drop that can be generated by the valve. The predicted MR valve performances are then experimentally evaluated using an oscillation-disturbed bypass hydraulic cylinder. The simulation results show that the proposed MR valve design could yield substantial pressure drop improvement, which is confirmed by the experiment.

Application of an Active Anti-roll bar system for enhancing vehicle ride and handling

More papers are written about Active Anti-roll bars (AARB) in automotive and mechanical field. These systems are usually designed for vehicles to change the roll stiffness of the vehicle, thus preventing a potential roll-over. In this present paper, the use of AARB will be analysed from two different perspectives in ride and handling. First, this paper proposed the basic vehicle dynamic modeling with four DOF (degree of freedom) on half car model are described that show, why and how it is possible to control the handling and ride comfort of the car, with the external forces on the front anti-roll bar. Basically, this paper is focused on understanding the vehicle dynamic behaviour under the influence and the effects of anti-roll bar mechanism. Simulated tests are presented, that shows how the characteristics of the body roll angle and roll rate responses by using MATLAB/SIMULINK software. By simulation analysis, the design model is validity and the performance under control of PID controller is achieved. Finally, some basic conclusions are drawn about the applicability of the possible control strategies will be investigated for such system in the future.

A new class of magnetorheological elastomers based on waste tire rubber and the characterization of their properties

This paper proposes a new type of magnetorheological elastomer (MRE) using rubber from waste tires and describes its performance characteristics. In this work, scrap tires were utilized as a primary matrix for the MRE without incorporation of virgin elastomers. The synthesis of the scrap tire based MRE adopted a high-temperature high-pressure sintering technique to achieve the reclaiming of vulcanized rubber. The material properties of the MRE samples were investigated through physical and viscoelastic examinations. The physical tests confirmed several material characteristics - microstructure, magnetic, and thermal properties-while the viscoelastic examination was conducted with a laboratory-made dynamic compression apparatus. It was observed from the viscoelastic examination that the proposed MRE has magnetic-field-dependent properties of the storage modulus, loss modulus, and loss tangent at different excitation frequencies and strain amplitudes. Specifically, the synthesized MRE showed a high zero field modulus, a reasonable MR effect under maximum applied current, and remarkable damping properties.

Development of a modular MR valve using meandering flow path structure

The extensive development of the magnetorheological (MR) valve has successfully introduced a new high-performance compact-class MR valve using a meandering flow path structure. Aside from the performance improvement, in real applications, the ease of performance adjustment also needs to be improved. This study focused on the development of a new design of a modular MR valve using a meandering flow path to improve the adjustability of the valve performance. The approach is proposed based on the high-performance advantages of a meandering flow path structure, while at the same time utilizing the benefit of the modular structure in terms of performance flexibility. In order to evaluate the performance of the modular structure, the analytical assessment was conducted for three different module stages: the single-stage module, the double-stage module, and triple-stage module. To predict the strength of the magnetic field in the effective area, the magnetic simulation was conducted through an open-source software called the FEMM (Finite Element Method Magnetics). The quasi-steady mathematical model of the proposed valve was also derived to conduct the analytical assessment as well as to predict the valve performance. In order to validate the simulation results, the prototypes of the proposed valve are experimentally tested with the aid of the hydraulic cylinder on a dynamic test machine. The results of the MR valve assessment from both the simulation and experimental test demonstrated that the pressure drop rating of the meandering type MR valve can be easily modified using modular structure by changing the number of module stages.

Influence of piston and magnetic coils on the field-dependent damping performance of a mixed-mode magnetorheological damper

This work presents a 2D simulation study of a mixed-mode magnetorheological (MR) damper in which the influence of the geometric elements of the piston and magnetic coil on the MR dampers performance is investigated by using the Ansoft Maxwell software tool. Four results of the simulation, which are magnetic flux density (B), MR fluid yield stress (τ 0), and are used to compare the performance of the MR damper. Multiplication of the yield stress by the active operating mode length represents the variable portion of the active (on-state) damping force of the flow mode motion, while the value of represents the active damping force of the shear mode motion. The contribution of each operating mode (shear and flow) is related to the mixed-mode geometry and piston velocity. Therefore, each operating mode is evaluated separately. In this work, a total of 154 simulations are done in which 74, 20 and 60 simulations are conducted to analyse the effect of the piston radius, coil dimensions (width and length) and coil boundary lengths, respectively, on the performance of the MR damper. The simulation results show that increasing the piston radius can increase the value and reduce the value. For a given area of magnetic coil housing, a greater housing length in the axial direction of the piston can increase the achieved yield stress of the MR fluid and hence consequently the performance of the MR damper. A minimum boundary length is needed around the magnetic coil in order to attain a supreme magnetic field distribution. However, there is an optimised value for axial coil boundary lengths, which are the lengths of the upper and lower mixed-mode areas.

Rheological properties of isotropic magnetorheological elastomers featuring an epoxidized natural rubber

This study presents principal field-dependent rheological properties of magnetorheological elastomers (MREs) in which an epoxidized natural rubber (ENR) is adopted as a matrix (in short, we call it ENR-based MREs). The isotropic ENR-based MRE samples are fabricated by mixing the ENR compound with carbonyl iron particles (CIPs) with different weight percentages. The morphological properties of the samples are firstly analysed using the microstructure assessment. The influences of the magnetic field on the viscoelastic properties of ENR-based MREs are then examined through the dynamic test under various excitation frequencies. The microstructure of MRE samples exhibits a homogeneous distribution of CIPs in the ENR matrix. The dramatic increment of storage modulus, loss modulus and loss tangent of the ENR-based MREs are also observed from the field-dependent rheological test. This directly demonstrates that the stiffness and damping properties of the samples can be adjusted by the magnetic field. It is also seen that the CIP content, exciting frequency and the magnetic field essentially influence the dynamic properties of the ENR-based MREs. The strong correlation between the magnetization and the magneto-induced storage modulus could be used as a useful guidance in synthesizing the ENR-based MREs for certain applications.

Bypass Rotary Magnetorheological Damper for Automotive Applications

A novel concept of bypass rotary Magneto-rheological (MR) damper is studied in the automotive suspension application. The proposed design is developed based on a vane-type damper structure with an MR control valve located outside of the damper. The design is intended to enhance the ease of maintenance and to reduce the thermal effect from the coil to the MR fluid. The valve is the key component of the damper that exploits the advance characteristics of MR fluid in which have sensitive rheological properties to magnetic field. The ability of the valve to modify the strength of magnetic field has given an advantage that the valve can be operated without any moving parts. The elimination of these parts in the throttling mechanism of the valve will provide benefit in terms of product lifetime and responsiveness. The main objective of this paper is to elaborate the advantages of the bypass rotary MR damper and to demonstrate the damper performance through force-velocity characteristics. The analytical model of the damper is developed and used in the determination of the force-velocity curves and the equivalent damping coefficients.

Design of magnetorheological valve using serpentine flux path method

Magnetorheological (MR) valve is widely applied in a lot of applications that utilizes the flow mode, which is one of the working modes available for MR fluid devices. This paper introduces the serpentine flux path method in an MR valve, whereby using this method it can help to increase the effective region of the valve. The magnetic flux is guided into the annular gap of the valve, as the magnetic flux can be weaved by alternating the magnetic and non-magnetic materials. The method is simulated using Finite Element Method Magnetics to see the effects of weaving steps and thicknesses of non-magnetic materials to the magnetic flux distribution and pressure drop change in the valve. The results show that MR effective region can be increased with the serpentine flux path method, and the additional steps and thicknesses of non-magnetic materials help to further increase the pressure drops within the valve.