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.

A rheological evaluation of steady shear magnetorheological flow behavior using three-parameter viscoplastic models

Abstract: Knowledge of the complicated flow characteristics of magnetorheological (MR) suspensions is necessary for simulations, calculations in engineering processes, or designing new devices utilizing these systems. In this study, we employed three constitutive equations (three-parameter models) for an evaluation of steady shear behavior of MR suspensions. The predictive/fitting capabilities of the Robertson–Stiff (R–S) model were compared with the commonly used Herschel–Bulkley (as a reference) and the Mizrahi–Berk models. The appropriateness of the models was examined using rheological data for diluted as well as concentrated MR systems. The effect of magnetic field strength on model fitting capabilities was also investigated. The suitability of the individual models was evaluated by observing correlation coefficient, sum of square errors, and root mean square errors. A statistical analysis demonstrated that the best fitting capabilities were exhibited by the R–S model, while others provided less accurate fits ...

Fast Response MR-Fluid Actuator

Abstract: Magnetorheological (MR) fluids are materials that change their rheological behavior upon applying a magnetic field. They have been promising as functional fluids that can improve the properties of mechanical systems. We have developed an actuator using MR fluid. In the previous paper, a method of designing MR-fluid actuators was proposed on the basis of magnetic circuit theory. The basic experiments were carried out and static properties that agreed well with the design were obtained. However, the transient response, which was not considered in the design phase, was not very fast. In this study, we investigate the dynamics of the MR-fluid actuator and aim to improve the response. The transient magnetic analysis is examined in consideration of the eddy current. Two approaches to improving the response are proposed. Finally, we realize a much faster MR-fluid actuator.

Experimental verification of torsional response control of asymmetric buildings using mr dampers

Abstract: This paper proposes a semiactive control system to reduce the coupled lateral and torsional motions in asymmetric buildings subjected to horizontal seismic excitations. Magnetorheological (MR) dampers are applied as semiactive control devices and the control input determination is based on a clipped-optimal control algorithm which uses absolute acceleration feedback. The performance of this method is studied experimentally using a 2-story building model with an asymmetric stiffness distribution. An automated system identification methodology is implemented to develop a control-oriented model which has the natural frequencies observed in the experimental system. The parameters for the MR damper model are identified using experimental data to develop an integrated model of the structure and MR dampers. To demonstrate the performance of this control system on the experimental structure, a shake table is used to reproduce an El Centro 1940 N–S earthquake as well as a random white noise excitation. The responses for the proposed control system are compared to those of passive control cases in which a constant voltage is applied to the MR damper. Copyright © 2003 John Wiley & Sons, Ltd.

Development of Universal Robot Gripper Using MRα Fluid

Abstract: In this paper, we developed a universal robot gripper using an electromagnet and a novel reforming magnetorheological (MR) fluid. First, we added nonmagnetic particles to an MR fluid to develop a novel reforming MR fluid called MRα fluid; this fluid resolved several issues faced with MR fluids. The developed fluid’s specific gravity is one-half and solidification hardness is two times that of MR fluid. The characteristics of the MRα fluid and an application that can control solidification under a magnetic field are described. Next, the developed gripper, which consists of an electromagnet and an elastic membrane that encloses the MRα fluid, is described. Further, several experimental results of the features and capabilities of the gripper are presented.

Application potential of magnetic field driven new actuators

Abstract: Most of the magnetic field driven actuators can be classified as electromagnetic, electrodynamic, magnetostrictive or magnetorheological (MR). While the first two mentioned have been known for a long time and are widely distributed, the actuators of the latter two groups have been gaining importance only in the last few years. In this paper, the principle, design and structure of magnetostrictive and MR actuators are presented. Typical examples illustrate their application potential which is clarified further by comparing the properties of their dual alternatives, namely, electrostrictive/piezoelectric and electrorheological actuators.