Magnetorheological fluid

About: Magnetorheological fluid is a research topic. Over the lifetime, 8538 publications have been published within this topic receiving 131502 citations. The topic is also known as: MRF & MR fluid.

Against the flow

Abstract: This article looks at the development and applications of electro-rheological (ER) and magneto-rheological (MR) devices in suspension systems, particularly in high-performance cars. ER or MR fluid features solid particulates in a host liquid. In the case of ER fluids, an applied electric field induces polarisation and aggregation of the particles: in MR fluids, the particles align into fibrous structures. This change in viscosity is reversible, so that the fluids are tunable in real time with high accuracy. A fluid's usefulness is determined by the magnitude of stresses it can resist. MR fluids have more uses currently than ER, with primary suspension systems for vehicles the main application, including steer-by-wire in commercial vehicles. Bridge cable damping and vibration isolators for satellite launch vehicles are other uses. ER fluids can form the basis of compact actuating elements: they could be used in haptic prosthetic devices. Difficulties with both include the high voltages required and sensitivity to impurities. The suspended particles tend to settle, needing additives to enhancelubricity and modify viscosity. Research in the field is investigating combinations of particle materials and carrier liquids.

Energetic instability unjams sand and suspension.

Abstract: Jamming is a phenomenon occurring in systems as diverse as traffic, colloidal suspensions, and granular materials. A theory on the reversible elastic deformation of jammed states is presented. First, an explicit granular stress-strain relation is derived that captures many relevant features of sand, including especially the Coulomb yield surface and a third-order jamming transition. Then this approach is generalized, and employed to consider jammed magnetorheological and electrorheological fluids, again producing results that compare well to experiments and simulations.

Creep and recovery behaviors of magnetorheological elastomer based on polyurethane/epoxy resin IPNs matrix

Abstract: This paper mainly investigated the creep and recovery behaviors of magnetorheological elastomers (MRE) based on polyurethane/epoxy resin (EP) graft interpenetrating polymer networks (IPNs). The influences of constant stress level, content of EP, particle distribution, magnetic field and temperature on the creep and recovery behaviors were systematically investigated. As expected, results suggested that the presence of IPNs leads to a significant improvement of creep resistance of MRE, and creep and recovery behaviors of MRE were highly dependent on magnetic field and temperature. To further understand its deformation mechanism, several models (i.e., Findley's power law model, Burgers model, and Weibull distribution equation) were used to fit the measured creep and recovery data. Results showed that the modeling of creep and recovery of samples was satisfactorily conducted by using these models. The influences of content of EP and magnetic field on fitting parameters were discussed, and relevant physical mechanism was proposed to explain it qualitatively.

Magnetic properties of carbonyl iron particles in magnetorheological fluids

Abstract: Knowledge of the magnetic properties of dispersed magnetic particles is a prerequisite to the design an MR fluid with desired performance A term specific susceptibility is introduced for characterization of particle susceptibility The study was performed with the Bartington MS2B magnetic susceptibility system on small samples volume Specific magnetic susceptibility of iron particles was found to be a linear function of median particle size Structural change in the fluid, including particle organization, led to susceptibility drift and may affect fluid performance It was shown that susceptibility data can be used for evaluation of the concentration of carbonyl iron particles in MR fluids