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†

Smart materials are kinds of designed materials whose properties are controllable with the application of external stimuli such as the magnetic field, electric field, stress, and heat. Smart materials whose rheological properties are controlled by externally applied magnetic field are known as magneto-rheological materials. Magneto-rheological materials actively used for engineering applications include fluids, foams, grease, elastomers, and plastomers. In the last two decades, magneto-rheological materials have gained great attention of researchers significantly because of their salient controllable properties and potential applications to various fields such as automotive industry, civil environment, and military sector. This article offers a recent progressive review on the magneto-rheological materials technology, especially focusing on numerous application devices and systems utilizing magneto-rheological materials. Conceivable limitations, challenges, and comparable advantages of applying these magn...

A state of art on magneto-rheological materials and their potential applications:

This paper presents a study on continuously variable stiffness control of vehicle seat suspension using a magnetorheological elastomer (MRE) isolator. A concept design for an MRE isolator is proposed in the paper and its behavior is experimentally evaluated. An integrated seat suspension model, which includes a quarter-car suspension and a seat suspension with a driver body model, is used to design a sub-optimal controller for an active isolator. The desired control force generated by this active isolator is then emulated by the MRE isolator through its continuously variable stiffness property when the actuating condition is met. The vibration control effect of the MRE isolator is evaluated in terms of driver body acceleration responses under both bump and random road conditions. The results show that the proposed control strategy achieves better vibration reduction performance than conventional on–off control.

http://iopscience.iop.org/article/10.1088/0964-1726/20/10/105003/pdf

Semi-active variable stiffness vibration control of vehicle seat suspension using an MR elastomer isolator

A tunable stiffness and damping vibration isolator based on magnetorheological elastomers (MREs) is developed. In this isolator, four MRE elements are used as the tunable springs, whose stiffness c...

Development of a real-time tunable stiffness and damping vibration isolator based on magnetorheological elastomer

This article presents the development of an active-damping-compensated magnetorheological elastomer (MRE) adaptive tuned vibration absorber (ATVA). The principle and the vibration attenuation performance of the proposed active-damping-compensated ATVA were theoretically analyzed. Based on the analysis, a prototype was designed and manufactured. Its dynamic properties and vibration attenuation performances were experimentally investigated. The experimental results demonstrated that the damping ratio of the prototype was significantly reduced by the active force. Consequently, its vibration attenuation capability was significantly improved compared with a conventional MRE ATVA.

An Active-damping-compensated Magnetorheological Elastomer Adaptive Tuned Vibration Absorber

A Semi-Active Vibration Absorber (SAVA) can suppress the vibration with time-varying frequency by tuning its natural frequency to track the excitation frequency. This paper presents the development of a mechanical SAVA whose natural frequency can be adjusted in real time by adjusting its geometry parameters. The principle and dynamic properties of the SAVA were theoretically analyzed. Based on these analyses, a prototype SAVA was designed and implemented. An optimum variable step-size control strategy of the SAVA was investigated. This control strategy is made up by two stages: the roughly tuning stage and the optimization stage. Some experiments were conducted to evaluate the dynamic properties and vibration attenuation performance of the SAVA. The experimental results indicate that the developed SAVA can tune its natural frequency in a large frequency range and its vibration attenuation effect is significantly improved compared with a Tuned Vibration Absorber (TVA).

Development of a Mechanical Semi-Active Vibration Absorber

Additive manufacturing (AM) has many advantages over traditional manufacturing technologies as it allows the fabrication of lattice structures with complex designs and inherent features within a single part without any separation. Currently, lattice structures have wide application prospects due to their excellent mechanical performance and design freedom. This paper provides both experimental and numerical investigations for the failure behaviors of selective laser melting (SLM) Ti6Al4V lattice structures under uniaxial compressive loading. Lattice structures with different cell topologies and strut radii were chosen to conduct quasi-static compression simulations to examine their mechanical properties and failure modes. It is found that adding [Formula: see text]-direction struts in the loading direction could significantly improve the load-carrying capacity and the most superior mechanical properties were presented by FCCZ. The slopes of the double logarithmic relationship between the equivalent stiffness and the relative density of lattice structures can be distinguished as close to 1.0 and 3.0, implying bending-dominated or stretch-dominated behavior of lattice structures, respectively. For stretch-dominated lattice structures under uniaxial compression, FCCZ, BCCZ and FBCCZ, the failure modes would experience a transformation from strut buckling to fracture with the increase of strut radii, which is different from FCC and BCC demonstrated as the bending-dominated lattice structures. 

Xianmin Chen

Papers

An Active-damping-compensated Magnetorheological Elastomer Adaptive Tuned Vibration Absorber

Development of a Mechanical Semi-Active Vibration Absorber

Mechanical properties and failure modes of additively manufactured Ti6Al4V lattice structures under quasi-static compressive loading