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.

The Out-of-Roundness of the Internal Surfaces of Stainless Steel Tubes Finished by the Rotational–Magnetorheological Abrasive Flow Finishing Process

Abstract: This article reports the experimental findings about the improvement in out-of-roundness (OOR) of stainless steel tubes finished by Rotational–Magnetorheological Abrasive Flow Finishing (R-MRAFF) process. In this process, a rotating motion is provided to the magnetorheological polishing (MRP) medium by means of a rotating magnetic field, and simultaneously, a reciprocating motion is provided to the polishing medium by a hydraulic unit. By controlling these two motions, nano level uniform smooth mirror like finished surface has been achieved and simultaneously OOR of internal surface of tube is reduced. Experiments are planned according to the central composite rotatable design of response surface methodology based on the selected range of process parameters obtained from the preliminary experiments. Analysis of Variance (ANOVA) is conducted and contribution of each model term affecting OOR improvement is calculated. It has been found that R-MRAFF process potentially reduces roundness error of axisymmetric...

MudPad: localized tactile feedback on touch surfaces

Abstract: We present MudPad, a system that is capable of localized active haptic feedback on multitouch surfaces. An array of electromagnets locally actuates a tablet-sized overlay containing magnetorheological (MR) fluid. The reaction time of the fluid is fast enough for realtime feedback ranging from static levels of surface softness to a broad set of dynamically changeable textures. As each area can be addressed individually, the entire visual interface can be enriched with a multi-touch haptic layer that conveys semantic information as the appropriate counterpart to multi-touch input.

Investigation of the response time of magnetorheological fluid dampers

Abstract: The primary purpose of this paper is to investigate the response time of magnetorheological (MR) dampers and the effect of operating parameters. Rapid response time is desired for all real-time control applications. In this experimental study, a commercially available MR damper was tested and the response time was found for various operating conditions. The parameters considered include operating current, piston velocity, and system compliance. The authors define the response time as the time required to transition from the initial state to 63.2% of the final state, or one time constant. Using a triangle wave to maintain constant velocity across the damper, various operating currents ranging from 0.5 Amps to 2 Amps were applied and the resulting force was recorded. The results show that, for a given velocity, the response time remains constant as the operating current varies, indicating that the response time is not a function of the applied current. To evaluate the effect of piston velocity on response time, velocities ranging from 0.1 in/s to 3 in/s were tested. The results show that the response time decreases exponentially as the velocity increases, converging on some final value. Further analysis revealed that this result is an artifact of the compliance in the system. To confirm this, a series of tests were conducted in which the compliance of the system was artificially altered. The results of the compliance study indicate that compliance has a significant effect on the response time of the damper.

Controllable fluid rehabilitation device including a reservoir of fluid

Abstract: A controllable fluid device (20) for rehabilitation of injured or weakened complex appendages such as the hands and feet. The controllable fluid device (20)includes a reservoir (34)which contains a sufficient amount of controllable fluid (52)such as a Magnetorheological (MR) fluid. A magnetic field generator (36)provides the magnetic field (H) which is applied to the controllable fluid (52) by a magnetic circuit (60). In one aspect, an electromagnet including a coil (58) and core (54) provides the magnetic field (H). The intensity of the magnetic field is controlled via a controller (38). In another aspect, the magnetic field (H) is provided by a permanent magnet (44) and a mechanical shunt mechanism (42) is used to vary the magnetic field intensity. Other embodiments include a heater unit (66) with optional thermostat (74).