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

FEM prediction of welding residual stress and distortion in carbon steel considering phase transformation effects

https://cyberleninka.org/article/n/403409.pdf

A review of numerical analysis of friction stir welding

Prediction of welding distortion and residual stress in a thin plate butt-welded joint

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†

This paper describes a novel soft actuator using a magnetorheological elastomer. First, the material characteristics in the magnetization process and major contributing factors to magnetization of the magnetic elastomer are shown. Second, an actuator using a magnetorheological elastomer combined with an embedded electromagnet is proposed. The magnetic circuit when a current is applied is described and its operating principle is explained. Finally, the static and dynamic motions and dynamic stress of the actuator are determined by an experimental prototype and measurement setup.

Novel Soft Actuator Using Magnetorheological Elastomer

The friction stir welding (FSW) has been used widely in the field of industry. Numerical analysis models for FSW also have been developed and there are many papers about it. In these papers, the most frequently used method is finite element method or finite difference method. However, by employing these methods, it is difficult or troublesome to calculate the advective term both for momentum and temperature. It is also difficult to calculate the big deformation of the material. Moreover, complex process is required to analyse the dissimilar joining with respect to dealing with substance transfer. In this paper, to avoid these difficulties or troublesome processes, particle method is adopted for dissimilar FSW simulation. In particle method, advective term, substance transfer and surface deformation are calculated automatically mainly because that Lagrangian approach is used. Performing some of analysis for FSW, the effectivity of this method is verified.

Development of numerical simulation model for FSW employing particle method

This paper proposes a coupled method of finite-element method (FEM) and moving particle semi-implicit (MPS) method in order to analyze the spike shape of ferrofluid. In this method, magnetic field equation is calculated by FEM and fluid equation is calculated by MPS method.

Numerical analysis of transitional behavior of ferrofluid employing MPS method and FEM

The problem of emissivity change on metal surface complicates the temperature measurement of molten pools in infrared (IR) radiation thermometry. Therefore, an emissivity correction is one of the most important subjects in IR radiation thermometry. The objective of the present investigation is to develop an ultraviolet (UV) radiation thermometry, which is an emissivity correction free method. According to the Planck's law of radiation, it is evident that the effect of temperature on the spectral radiance is greater at the shorter wavelength, and radiation thermometry in UV range is expected to reduce the error caused by the emissivity change. Generally, the radiation energy in UV range is lower than that in IR range at the same temperature. A measurement system that is sensitive to the UV radiation has been developed in the present work. The system consists of an image intensifier, and multiple optical band-pass filters. In the present paper, two-dimensional temperature distribution on TIG weld pool has been measured by using the developed UV radiation thermometer. It is made clear that the luminance temperature distributions measured by IR and UV range are quite different, and the surface temperature on molten pool is affected by sulfur concentration in the material.

UV Radiation Thermometry of TIG Weld Pool-Development of UV Radiation Thermometry (Report 1)-

A feasibility study has been conducted to determine whether mathematical models can be used for the numerical simulation of metal active gas (MAG) arc welding In the present work, a three-dimensional, nonstationary thermal model for fillet welding is developed The transient temperature distribution in the base metal is numerically analysed to estimate the molten pool size using a finite difference model based on the heat flow equation, and the theoretical configuration of the molten pool is calculated, taking account of the balance of gravity, surface tension, and arc pressure The developed model can be applied to various welding processes such as multipass welding, lap welding, and welding with torch oscillation To evaluate the validity of the model analysis, the calculated results are compared with experimental results for MAG welding Good correspondence is demonstrated between experiment and calculation

Fumikazu Miyasaka

Papers

Novel Soft Actuator Using Magnetorheological Elastomer

Development of numerical simulation model for FSW employing particle method

Numerical analysis of transitional behavior of ferrofluid employing MPS method and FEM

UV Radiation Thermometry of TIG Weld Pool-Development of UV Radiation Thermometry (Report 1)-

Mathematical modelling of metal active gas arc welding