Papers by Keyword: MR Effect

Abstract: This article delineates the characterization of the 3D printed MR elastomer through a forced vibration technique in the squeeze mode of operation. An anisotropic hybrid magnetorheological (MR) elastomer is developed via 3D printing. The 3D printed MR elastomer consists of three different materials; magnetic particles, magnetic particles carrier fluid, and an elastomer. MR fluid filaments are encapsulated layer-by-layer within the elastomer matrix using a 3D printer. When a moderately strong magnetic field is applied, the 3D printed MR elastomer changes its elastic and damping properties. The hybrid 3D printed MR elastomer also shows an anisotropic behavior when the direction of the magnetic field is changed with respect to the orientation of the printed filaments. The relative MR effect is higher when the applied magnetic field is parallel to the orientation of the printed filaments. The maximum change in the stiffness is observed to be 65.2% when a magnetic field of 500 mT is applied to the MR elastomer system. This result shows that the new method, 3D printing could produce anisotropic hybrid MR elastomers or possibly other types.

Abstract: Magnetorheological (MR) elastomers are a new type of MR material. At present, most studies in this field are at laboratory stage, and practicability was rarely considered preparation of MR elastomer materials. Consequently, the existing materials with low overall properties cannot be applied in engineering. In this paper, the performance requirements for MR elastomers to be used in isolators were proposed. Then a type of practical MR elastomers for isolators was prepared, and its mechanical performance and MR effect were tested. The results show that the designed MR elastomers have high mechanical performance and high MR effect, and thus can be used in isolators.

Abstract: When the cylindrical NdFeB magnet was magnetized along the axle wire, the magnetic field around the magnet was symmetric about the axle wire. The output voltage of Hall sensor was proportional to magnetic induction induced by itself. Around the magnet, the magnetic induction component along the axle wire could be measured by Hall sensor. The contour line and contour surface of magnetic induction could be plotted by MATLAB. A sensor array was composed of three Hall sensors in triangular distribution, and 3D Cartesian Coordinate System was established. 3D coordinate of magnet can be measured with this sensor array based on contour surface. Underground soil deformation will change the relative position of sensor array and magnet. The size of geotechnical displacement can be calculated after getting the new 3D coordinate of magnet. Along with dual-axis magnetic sensor based on MR effect, the orientation of geotechnical displacement can be measured, and so able to measure the underground displacement.

Abstract: A new planarization polishing method, based on the cluster magnetorheological (MR) effect and using MR fluid to form the flexible polishing pad, is presented in this paper to polish optical glass. To explore the machining characteristic of the viscid and flexible polishing pad based on the cluster MR-effect, some process experiments were conducted to reveal the influence of the machining gap, the speed of the polishing disc and the polishing time on the machining effect. The results indicate that the viscid and flexible polishing pad based on the cluster MR-effect under a strong magnetic field can reduce surface roughness effectively. When the strength of the magnetic field is 2000Gs, and the content of the carbonyl iron is 12%, the surface roughness can be reduced rapidly from the original Ra0.27μm to Ra1.4nm based on the cluster MR-effect.

Abstract: A new planarization grinding method based on the cluster magnetorheological (MR) effect is presented to grind optical glass in this paper. Some process experiments were conducted to reveal the influence of the speed of the grinding disc and grinding time and grinding pressure during the machining process. The results indicate that the speed of the grinding disc influences definitively on grinding effect of this planarization grinding method based on the cluster MR-effect. When the speed of the grinding disc is 110r/min, better machining effect can be achieved. Furthermore, the influence of the grinding time on machining effect is obviously, and the proper machining time is 6mins. However, under the experiment condition in this paper, the influence of grinding pressure on machining effect is unobvious.

Abstract: Passive adaptive MR damper is a new type of damper based on GMM inverse effect and MR effect, and it doesn’t need energy devices and can realize external force self-adaptation. A model of passive adaptive MR damper is established based on Jiles-Atherton model, the law of approach for the magnetomechanical effect, the magnetic circuit law and Bingham model. Experimental results show that the value of damping force is related to displacement and velocity: the larger the displacement, the greater the damping force; the faster the speed, the greater the damping force. This is consistent with the model.

Abstract: A new planarization polishing method based on the cluster magnetorheological (MR) effect is presented to polish optical glass in this paper. Some process experiments were conducted to reveal the influence of the content of carbonyl iron and the abrasive materials in the MR fluid on the machining effect, and the machining characteristic of polished surface was studied. The results indicate that the surface roughness of the polished workpiece can be reduced rapidly when the strong magnetic field is applied, and ultra smooth surface with Ra 1.4 nm can be achieved while the CeO2 abrasives are used in the MR fluid. The content of carbonyl iron obviously influences the machining effect of this planarization polishing method based on cluster MR-effect. With the increase of the content of carbonyl iron in the MR fluid, the material removal rate improves and the surface roughness reduces rapidly. However, the difference of abrasive material results in various machining effects. As for the K9 optical glass, the CeO2 abrasive is better polishing abrasive than the SiC abrasive in the planarization polishing technique based on the cluster MR-effect.