Magnetorheological (MR) ﬂuid is a kind of smart materials with rheological behavior change by means of external magnetic ﬁeld application, which has been widely adopted in many complex systems of different technical fields. In this work, the state-of-the-art MR ﬂuid-based devices are reviewed according to structural configurations reported from 2018 to 2020. Based on the rheological characteristic, MR fluid has a variety of operational modes, such as ﬂow mode, shear mode, squeeze mode and pinch mode, and plays unique advantages in some special practical applications. Thus, referring to these operational modes, improved engineering mechanical devices with MR fluid are summarized including brakes, clutch, damper and mount proposed over the last three years. Furthermore, some new medical devices used MR fluid are also investigated, for instance, surgical assistive devices and artificial limb. In particular, some outstanding advances on structural innovations and application superiority of these devices are introduced in detail. Finally, an overview of the significant issues occurred in the MR fluid-based devices is reported, and the developing trends are discussed for the devices with MR fluid.

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A Review on Structural Configurations of Magnetorheological Fluid Based Devices Reported in 2018-2020

The potential implications/applications of printing technologies are being recognized worldwide across different disciplines and industries. Printed magnetoactive smart materials, whose physical properties can be changed by the application of external magnetic fields, are an exclusive class of smart materials that are highly valuable due to their magnetically activated smart and/or multifunctional response. Such smart behavior allows, among others, high speed and low-cost wireless activation, fast response, and high controllability with no relevant limitations in design, shape, or dimensions. Nevertheless, the printing of magnetoactive materials is still in its infancy, and the design apparatus, the material set, and the fabrication procedures are far from their optimum features. Thus, this review presents the main concepts that allow interconnecting printing technologies with magnetoactive materials by discussing the advantages and disadvantages of this joint field, trying to highlight the scientific obstacles that still limit a wider application of these materials nowadays. Additionally, it discusses how these limitations could be overcome, together with an outlook of the remaining challenges in the emerging digitalization, Internet of Things, and Industry 4.0 paradigms. Finally, as magnetoactive materials will play a leading role in energy generation and management, the magnetic-based Green Deal is also addressed.

Magnetic materials: a journey from finding north to an exciting printed future

Effect and its mechanism of spatial coherence of track irregularity on dynamic responses of railway vehicles

Dynamic modelling and control of shear-mode rotational MR damper for mitigating hazard vibration of building structures

Theoretical and experimental investigation of a stiffness-controllable suspension for railway vehicles to avoid resonance

Development and evaluation of a versatile semi-active suspension system for high-speed railway vehicles

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Vibration control of a tunnel boring machine using adaptive magnetorheological damper

The utility model relates to a self-energized variable rigidity and damping magneto-rheological shock absorber which comprises a rod piece, an inner cylinder, an outer cylinder, an upper cover and a spring. A shaft shoulder is arranged at one end of the rod piece; the other end extends into the inner cylinder; the rod piece can axially move relative to the inner cylinder, the upper cover is fixed to the end, away from the rod piece, of the inner cylinder, the excitation coil surrounds the outer wall of the inner cylinder, the outer cylinder is arranged on the outer wall of the inner cylinder in a sleeving mode and can axially move relative to the inner cylinder, the two ends of the outer cylinder are sealed through outer cylinder covers respectively, and the space between the outer cylinder and the inner cylinder is filled with magnetorheological fluid. One end of the spring is in contact with the shaft shoulder of the rod piece, and the other end of the spring is in contact with the first outer cylinder cover; a coil sleeve is arranged in the inner cylinder, and a self-induction coil is wound on the coil sleeve; a permanent magnet is arranged on the outer wall of one end of the inner cylinder. The problems that the rigidity and damping parameters of an existing shock absorber cannot be changed in real time according to the structural vibration condition, energy cannot be generated by the existing shock absorber, and structural vibration cannot be well attenuated are solved.

Tianhe Jin

Papers

Development and evaluation of a versatile semi-active suspension system for high-speed railway vehicles

Theoretical and experimental investigation of a stiffness-controllable suspension for railway vehicles to avoid resonance

Vibration control of a tunnel boring machine using adaptive magnetorheological damper

Self-powered variable rigidity and damping magneto-rheological shock absorber