Papers by Keyword: Magnetorheological Effect

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Authors: Jia Bin Lu, Juan Yu, Qiu Sheng Yan, Wei Qiang Gao, Liang Chi Zhang
Abstract: Based on the magnetorheological (MR) effect of abrasive slurry, this paper presents an innovative superfine machining method. In this technique, the particle-dispersed MR fluid is used as a special instantaneous bond to cohere abrasive particles and magnetic particles so as to form a dynamical tiny-grinding wheel. This tiny-grinding wheel can be used to polish the surface of brittle materials in millimeter or sub-millimeter scale. The characteristics of the machined glass surfaces examined by the scanning electron microscope (SEM) and the Talysurf roughness tester confirmed the effectiveness of the finishing technique. The machined surface with convex center and concave fringe demonstrates that the material removal process is dominated by the synergy of the applied pressure and the relative velocity between the abrasives and workpiece. In the case of glass finishing, the mode of material removal is found to be plastic, and controlled by the abrasive-wear mechanism.
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Authors: Zhi Wei Zhu, Guang Xue Chen, Qi Feng Chen, Bao Lin Tang
Abstract: As one of the intelligent materials, Magnetorheological Fluid is dispersions composed of soft magnetic particles, carrier liquid and additives. The apparent yield strength of Magnetorheological Fluid can be changed significantly within milliseconds by the application of an external magnetic field. As the key elements of the three-dimensional imaging, the three-dimensional grating is a special material composed of cylindrical lens. Because water-based magnetorheological fluid has a unique magnetorheological effect, good rheological properties and environment-friendly performance, it is applied to the production of three-dimensional printing grating, through the change of the magnetorheological fluid to control the exact distribution of the soft magnetic particles, so as to achieve the desired accuracy, light transmittance and stability of printing raster, and finally present a ideal three-dimensional effect after laminating the grating and three-dimensional images.
435
Authors: Qiu Sheng Yan, Ai Jun Tang, Jia Bin Lu, Wei Qiang Gao
Abstract: A new plate polishing technique with an instantaneous tiny-grinding wheel cluster based on the magnetorheological (MR) effect is presented in this paper, and some experiments were conducted to prove its effectiveness and applicability. Under certain experimental condition, the material removal rate was improved by a factor of 20.84% as compared with the conventional polishing methods with dissociative abrasive particles, while the surface roughness of the workpiece was not obviously increased. Furthermore, the composite of the MR fluid was optimized to obtain the best polishing performance. On the basis of the experimental results, the material removal model of the new plate polishing technique was presented.
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Authors: Qiu Sheng Yan, Yong Yang, Jia Bin Lu, Wei Qiang Gao
Abstract: Experiments were conducted to polish optical glass with the magnetorheological (MR) effect-based tiny-grinding wheel cluster, and the influences of abrasive material, particle size and content on the material removal rate and surface roughness are investigated. The experimental results indicate that: the higher the hardness of abrasives, the higher the material removal rate, but the abrasives with lower hardness can obtain lower surface roughness. The better polishing quality of the workpiece can be obtained when the particle size of abrasives is similar to the particle size of magnetic particles. Moreover, the content of abrasives has an optimum value, and the material removal rate and the surface quality can not be improved further when the content of abrasives exceeds the optimum value. On the basis of above, the material removal model of the new planarization polishing technique is presented.
229
Authors: Jie Wen Yan, Qiu Sheng Yan, Jia Bin Lu, Wei Qiang Gao
Abstract: A new tiny-grinding wheel cluster polishing method based on the Magnetorheological (MR) effect is presented to polish optical glass in this paper and some process experiments were conducted to reveal the influence of magnetic field strength, the content of carbonyl iron in the MR fluid and the speed of polishing disc on the material removal rate and the surface roughness of the glass workpiece. The results indicate that when the external magnetic field is applied, the material removal rate of the workpiece improves rapidly but the surface roughness increases slightly. When the Magnetic field strength is 100 Gs and the content of carbonyl iron is 3.5%, the material removal rate improves by a factor of 16.8% compared with that of the conventional polishing methods with dissociative abrasive particles, while the surface roughness of the workpiece increases unobviously.
406
Authors: Qian Jin, Yong Gang Xu, Yang Di, Hao Fan
Abstract: In this paper, the correlation between the particle size and rheological properties of MRE was discussed through both experimental results and theoretical analysis. It shows that the particle size can significantly influence the magnetorheological effect by changing the initial shear modulus and the saturated magnetic-induced shear modulus . With an increase in the particle size, the initial shear modulus gets lower, and the saturated magnetic-induced shear modulus increases to the maximum and then decreases. The larger the particle size is, the longer the distance between neighbor particles along the magnetic field is. Based on the relationship between the particle size and shear modulus, there exists an optimum size for added particles. Moreover, the performance of MRE can be improved by optimizing the particle size based on those rules.
757
Authors: Xue Yang, Chang Geng Shuai, Shen Lin Yang
Abstract: The dynamic magnetorheological (MR) effects of 1,5-Naphthalene diisocyanate (NDI) polyurethane-based MR elastomers were tested by changing excitation frequency, excitation amplitude, magnetic strength, or preload. NDI polyurethane-based elastomers show high dynamic mechanical property, and were used as base material to prepare MR elastomers, whose mechanical performance and dynamic MR effect were tested. The results show that: (1) the prepared NDI polyurethane-based MR elastomers have high mechanical performance and MR effect; (2) their MR effect was reduced with the increase in excitation amplitude or preload, but did not change obviously with the increase in excitation frequency. Therefore, MR elastomer devices should be reasonably designed to maximize MR effect.
832
Authors: Muntaz Hana Ahmad Khairi, Saiful Amri Mazlan, Ubaidillah, Siti Aishah Abdul Aziz, Norhiwani Mohd Hapipi
Abstract: This study introduces a sucrose acetate isobutyrate (SAIB) as an additive of magnetorheological elastomers (MREs) to be added in silicone rubber matrix and carbonyl iron particles (CIPs) as their filler. The CIPs were fixed at 60 wt% and two types of MREs sample were fabricated which are isotropic and anisotropic. Rheological properties related to shear storage modulus were measured using a rheometer (MCR 302, Anton Paar). The experimental results demonstrated that the magnetorheological (MR) effect of anisotropic MREs-based Silicone/SAIB was 126 % as compared to isotropic MREs-based Silicone/SAIB, 64%. The fabricated MREs samples were frequency and strain dependent. The relative MR effect for both samples showed decreasing trend with the increment of strain amplitude and excitation frequency.
61
Authors: Guo Fa Li, Ming Zuo Han, Cui Yun Shan, Jia Liu, Jun Xiang Yang
Abstract: The dual characteristic of magnetorheological rheology and phase transitions is studied and its rheological principle is also described. By using the ANSYS finite element method, a simulation analysis of the torque transmission model is conducted. By selecting the magnetorheological fluid SG-MRF2035, a magneto-rheological torque servo device prototype (Gap of 1.5mm) is developed. And a performance testing platform is built for the torque output characteristics of prototype. The test results show that the device could provide supple output torque and the torque is continuously adjustable. This paper provides a new way for the wide application of magnetorheological fluids.
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Authors: Juan Yu, Qiu Sheng Yan, Jia Bin Lu, Wei Qiang Gao
Abstract: Based on the magnetorheological (MR) effect of abrasive slurry, the particle-dispersed MR fluid is used as a special instantaneous bond to cohere abrasive particles and magnetic particles so as to form a dynamic, flexible tiny-grinding wheel to polish optical glass, ceramic and other brittle materials of millimeter or sub-millimeter scale with a high efficiency. Experiments were conducted to reveal the effects of different process parameters, such as grain sizes of abrasive particles, machining time, machining gap between the workpiece and the rotation tool, and rotation speed of the tool, on material removal rate of glass surface. The results indicate the following conclusions: material removal rate increases when the grain size of abrasives is similar to that of magnetic particles; machining time is directly proportional to material removal, but inversely proportional to material removal rate; machining gap is inversely proportional to material removal; polishing speed has both positive and negative influence on material removal rate, and greater material removal rate can be obtained at a certain rotation speed. In addition, the difference of the machining characteristics between this new method and the traditional fixed-abrasive machining method is analyzed.
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