During the last few decades, magnetorheological (MR) elastomers have attracted a significant amount of attention for their enormous potential in engineering applications. Because they are a solid counterpart to MR fluids, MR elastomers exhibit a unique field-dependent material property when exposed to a magnetic field, and they overcome major issues faced in magnetorheological fluids, e.g. the deposition of iron particles, sealing problems and environmental contamination. Such advantages offer great potential for designing intelligent devices to be used in various engineering fields, especially in fields that involve vibration reduction and isolation. This paper presents a state of the art review on the recent progress of MR elastomer technology, with special emphasis on the research and development of MR elastomer devices and their applications. To keep the integrity of the knowledge, this review includes a brief introduction of MR elastomer materials and follows with a discussion of critical issues involved in designing magnetorheological elastomer devices, i.e. operation modes, coil placements and principle fundamentals. A comprehensive review has been presented on the research and development of MR elastomer devices, including vibration absorbers, vibration isolators, base isolators, sensing devices, and so on. A summary of the research on the modeling mechanical behavior for both the material and the devices is presented. Finally, the challenges and the potential facing magnetorheological elastomer technology are discussed, and suggestions have been made based on the authors’ knowledge and experience.

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A state-of-the-art review on magnetorheological elastomer devices

Magnetorheological (MR) materials are classified as smart materials due to their responsiveness to external magnetic stimuli. Intensive research on MR materials has led to broad applications in several potential fields. A solid carrier matrix state called MR elastomer with its exceptional magnetic responsive feature is obtained by merging magnetizable particles within an elastomeric polymer. This integration results in outstanding characteristics on the rheological performances. Special prominence is given to the understanding of the base materials and fabrication as well as the functional behavior through various characterization methods. Broad applications of MREs are also explored to provide a profound market picture and to motivate researchers to develop novel technology. The functional behavior of MREs is briefly explained. The art of the materials provides the current position and mapping of the matrix and filler particles. Types of matrix and particles are mentioned together with the level of the research interest on MREs. Description of the fabrication is provided in simple diagrams as summarized from previous works to enhance the MREs performance. The possible tests to reveal the characteristics of the MREs are delivered with the global experimental setup. The review also explains the applications of MREs as well as discussion on the MREs future promising applications.

Recent Progress on Magnetorheological Solids: Materials, Fabrication, Testing, and Applications†

Magnetorheological elastomers (MREs) are a class of recently emerged smart materials whose moduli are largely influenced when exposed to an external magnetic field. The MREs are particulate composites, where micro-sized magnetic particles are dispersed inside a non-magnetic polymeric matrix. These elastomers are known for changing their mechanical and rheological properties in the presence of a magnetic field. This change in properties is widely known as the magnetorheological (MR) effect. The MR effect depends on a number of factors such as type of matrix materials, type, concentration and distribution of magnetic particles, use of additives, working modes, and magnetic field strength. The investigation of MREs’ mechanical properties in both off-field and on-field (i.e. absence and presence of a magnetic field) is crucial to deploy them in real engineering applications. The common magneto-mechanical characterization experiments of MREs include static and dynamic compression, tensile, and shear tests in both off-field and on-field. This review article aims to provide a comprehensive overview of the magneto-mechanical characterizations of MREs along with brief coverage of the MRE materials and their fabrication methods.

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A review on magneto-mechanical characterizations of magnetorheological elastomers

Large-strain behaviour of Magneto-Rheological Elastomers tested under uniaxial compression and tension, and pure shear deformations

Magnetorheological elastomers (MREs) are novel class of magneto-active materials comprised of micron-sized ferromagnetic particles impregnated into an elastomeric matrix, which exhibit variable stiffness and damping properties in a reversible manner under the application of an external magnetic field. Characterization of highly complex behavior of these active composites is a fundamental necessity to design adaptive devices based on the MREs. This study is mainly concerned with in-depth experimental characterizations of static and dynamic properties of different types of MREs using methods defined in related standards. For this purpose, six different types of MRE samples with varying contents of rubber matrix and ferromagnetic particles were fabricated. The static characteristics of the samples were experimentally evaluated in shear mode as a function of the magnetic flux density. The particular MRE sample with highest iron particles content (40% volume fraction) was chosen for subsequent dynamic characterizations under broad ranges shear strain amplitude (2.5–20%), excitation frequency (0.1–50 Hz) and applied magnetic flux densities (0–450 mT). The results revealed nearly 1672% increase in the MRE storage modulus under the application of a magnetic flux of 450 mT, which confirms the potential of the novel fabricated MRE for control of vibration and noise in various engineering applications.

On the properties of magnetorheological elastomers in shear mode: Design, fabrication and characterization

In this study, the behavior of thick magnetorheological elastomers is experimentally investigated. Two types of magnetorheological elastomer specimens of varying concentrations, with circular and rectangular shapes having thicknesses from 6.35 mm to a maximum of 25.4 mm, are prepared. The magnetorheological elastomer samples are studied under quasi-static compression and double lap-shear tests. The shear and the Young’s moduli of the magnetorheological elastomers are obtained under different applied magnetic fields. It is observed that the field-induced change in the modulus is independent of the thickness of the magnetorheological elastomer and is only dependent on the iron particle concentration and the magnetic field strength. With the increase in the applied magnetic field, it is observed that the change in modulus varies from a linear behavior at lower applied magnetic fields to a nonlinear one at higher magnetic fields. It is found that compressive and shear moduli only depend on the applied magneti...

Behavior of thick magnetorheological elastomers

In the present study, two types of MRE with different concentrations, and circular and rectangular shapes having thicknesses from 6.35mm to a maximum of 25.4mm are prepared. These samples are tested under quasi-static compression and quasi-static double lap shear. It is observed that the measured off-state shear modulus has large variations with increase in the thickness of the sample. The measured shear modulus from the double lap shear test results, as well as the Young's modulus from the compression tests at zero-field, follows a logarithmic trend. With the increase in applied magnetic field, it is observed that the change in modulus shifted from a linear at lower field to a non-linear trend at higher fields. In addition it is observed that the controllability of MRE is more in the compression mode than in the shear mode . Keywords : Thick magnetorheological elastomers, shear , compression, damping, stiffness 1. INTRODUCTION Magnetorheological elastomers (MREs) are made by mixing micro-meter sized magnetizable particles with a non-magnetic elastomeric matrix. MREs are often referr ed to as the solid-state analogues of MR fluids

Praveen Mysore

Papers

Behavior of thick magnetorheological elastomers

Behavior of thick magnetorheological elastomers

Thick magnetorheological elastomers