Transient response of magnetorheological fluids: Shear flow between concentric cylinders

Ulicny, John C.; Golden, Mark A.; Namuduri, Chandra; Klingenberg, Daniel J.

doi:10.1122/1.1803576

Cited by 36 publications

(22 citation statements)

References 21 publications

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“…The transient response of MR fluids and MR elastomers under a stepwise magnetic field have been investigated by Ulicny et al [33] and Mitsumata et al [15], respectively. Here, G of different MR gels in response to a stepwise magnetic field were also tested ( figure 3(a)), from which we can further deduce the microstructure evolution process of MR gels driven by an external magnetic field.…”

Section: Dynamic Properties Under Oscillatory Shear Rheometrymentioning

confidence: 99%

“…A high solvent content will make the matrix become soft and a small G 0 can be tested. The damping of MR gels mainly comes from the movements of the soft segments in PU and the energy dissipation caused by interfacial slipping between iron particles and the matrix [33]. For solid-like MR gels, interfacial slipping hardly occurs, so the movements of the soft segments in PU are the main source of damping.…”

Section: Dynamic Properties Under Oscillatory Shear Rheometrymentioning

confidence: 99%

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Soft magnetorheological polymer gels with controllable rheological properties

Gong

Xuan

2013

Smart Mater. Struct.

100

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A series of magnetorheological (MR) gels consisting of plastic polyurethane matrix swollen by nonvolatile solvent in different weight fractions and carbonyl iron particles were prepared. Their magnetorheological properties, both under oscillatory and rotational shear rheometry, were systematically tested. The results demonstrate that except for the significant influence on the magnetorheological performance, the state of these MR gels can also be easily switched from solid-like (the solvent content is less than 10 wt%) to liquid-like (the solvent content exceeds 25 wt%) by adjusting the solvent content. The huge differences in magnetorheological properties of different MR gels (for example, the G of MR gels without solvent is three orders of magnitude larger than that of MR gels with 45 wt% of solvent in the absence of a magnetic field) and movements of iron particles in the presence of a magnetic field were analyzed, which are helpful in thoroughly understanding the mechanical-magnetic coupling mechanism between the magnetic particles and the polymer matrix and promoting the application of MR polymer gels. In addition, the stability of MR gels was also investigated. A gravity yield parameter was introduced to quantitatively describe the relationship between particle sedimentation and material characteristics. When the solvent content is lower than 25 wt% or the gravity yield parameter is larger than 0.865, the particle settling phenomenon can be effectively avoided.

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Section: Dynamic Properties Under Oscillatory Shear Rheometrymentioning

confidence: 99%

Section: Dynamic Properties Under Oscillatory Shear Rheometrymentioning

confidence: 99%

Soft magnetorheological polymer gels with controllable rheological properties

Gong

Xuan

2013

Smart Mater. Struct.

100

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“…The shear stress increased even for test times up to 10 s per point, which was much larger than the transient response time under stepwise magnetic fields. 16,17 For short time intervals between points, the shear stress was higher than the average stable counterparts in long shearing time [ Fig. 1(d)].…”

mentioning

confidence: 99%

Unexpected shear strength change in magnetorheological fluids

et al. 2014

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Smart materials of magnetorheological (MR) fluids could be turned from a liquid state into a solid state, which solidification extent or shear strength often increases monotonically with the applied magnetic field. In this study, the shear stress of a dilute MR fluid decreased with increasing applied magnetic field at a constant shear rate. The dynamic shear stress was significantly higher than the stable counterpart at medium magnetic fields. They are ascribed to the slow particle structure transformation. A higher shear rate and particle volume fraction could reduce the transient time and the shear strength difference.

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“…Other interesting consideration on the rheological behaviour of the MR fluids, especially considering the fluid-dynamics and the magneto-static of the system are investigated in [20] by using a Searle type rheometer equipped with several rotors, with square, round and lobate profiles. Ulicny [21] considers the variation in the MR fluid behaviour in presence of step changes of magnetic flux and shows that the viscous effect plays a minor role. The typical laboratory device used to test MR fluids is the magneto-rheometer and in [22] Schramm describes the factors which influence the behaviour of MR fluid inside a traditional rheometer with concentric cylinders.…”

Section: Introductionmentioning

confidence: 99%

Characterization of commercial magnetorheological fluids at high shear rate: influence of the gap

Golinelli¹,

Spaggiari²

2018

Smart Mater. Struct.

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This paper reports the experimental tests on the behaviour of a commercial MR fluid at high shear rates and the effect of the gap. Three gaps were considered at multiple magnetic fields and shear rates. From an extended set of almost two hundred experimental flow curves, a set of parameters for the apparent viscosity are retrieved by using the Ostwald de Waele model for non-Newtonian fluids. It is possible to simplify the parameter correlation by making the following considerations: the consistency of the model depends only on the magnetic field, the flow index depends on the fluid type and the gap shows an important effect only at null or very low magnetic fields. This lead to a simple and useful model, especially in the design phase of a MR based product. During the off state, with no applied field, it is possible to use a standard viscous model. During the active state, with high magnetic field, a strong non-Newtonian nature becomes prevalent over the viscous one even at very high shear rate; the magnetic field dominates the apparent viscosity change, while the gap does not play any relevant role on the system behaviour. This simple assumption allows the designer to dimension the gap only considering the non-active state, as in standard viscous systems, and taking into account only the magnetic effect in the active state, where the gap does not change the proposed fluid model.

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Transient response of magnetorheological fluids: Shear flow between concentric cylinders

Cited by 36 publications

References 21 publications

Soft magnetorheological polymer gels with controllable rheological properties

Soft magnetorheological polymer gels with controllable rheological properties

Unexpected shear strength change in magnetorheological fluids

Characterization of commercial magnetorheological fluids at high shear rate: influence of the gap

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