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Researcher: JOSHI S. B.
Guide(s): PAWAR P. M.
University: Solapur University
Completed Date: 21-08-2017
Abstract: This investigation is concerned with the development of a vibration reduction system using variable damping and stiffness devices. Magneto-Rheological Dampers (MRDs) and Magneto-Rheological Elastomers (MREs) are semi-active devices using principles of variable damping and stiffness, respectively. Through an extensive literature survey, theory of variable damping and stiffness was understood; design principles, fabrication methods of existing MRDs, MREs and their performances and applications were explored and scope of the work to be carried out and the methodology was finalized. Later, new MRDs and MREs were fabricated and their suitability and efficiencies for vibration reduction applications was tested experimentally. Existing MR dampers employ internal coil design, and there are certain limitations associated with these designs. In order to overcome these limitations, an innovative approach of retrofitting existing passive dampers into external coil MR dampers is suggested. Retrofitted damper consists of an external coil for applying the magnetic field, MR fluid contained in the modified damper tube. MR fluid samples constituting different carrier oils, carbonyl iron powder, and stabilizing agent were prepared using a reliable, repeatable and economical process in the research laboratory itself. Magneto-rheological properties of these fluids were evaluated through experiments. From the experimental data, exact compositions required to produce desired MR effects were found. Also, sedimentation properties of these MR fluids with different additive proportions were observed. Magnetic circuit in the form of an external coil was designed based on theoretical calculations and the efficiency of the coil producing the magnetic flux was tested through a number of trials. In some of the experiments, permanent magnets with high Gauss power were used to obtain newlineVII newlinedesired magnetic strength by adjusting the distance between South-North poles. Further, the existing passive damper was converted into a modified form by doing minor changes. The performance of the retrofitted external coil damper was experimentally evaluated in terms of force-velocity plots which exhibited controllable variable damping under the influence of magnetic field and showed almost 50% increase in the damping coefficient. Using spring-mass-damper in the form of 1DOF system, suitability of the retrofitted external coil MR damper to suspension systems was verified. newline
Appears in Departments:Department of Mechanical Engineering

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10_chapter 4.pdfAttached File3.39 MBAdobe PDFView/Open
11_chapter 5.pdf2.81 MBAdobe PDFView/Open
12_chapter 6.pdf491.69 kBAdobe PDFView/Open
13_chapter 7.pdf101.48 kBAdobe PDFView/Open
14_appendix.pdf12.05 MBAdobe PDFView/Open
15_references.pdf105.38 kBAdobe PDFView/Open
1_title.pdf30.69 kBAdobe PDFView/Open
2_certificates.pdf63.46 kBAdobe PDFView/Open
3_acknowledgement.pdf50.04 kBAdobe PDFView/Open
4_abstract.pdf51.51 kBAdobe PDFView/Open
5_toc.pdf69.83 kBAdobe PDFView/Open
6_list of tables figures.pdf515.81 kBAdobe PDFView/Open
7_chapter 1.pdf200.84 kBAdobe PDFView/Open
8_chapter 2.pdf3.04 MBAdobe PDFView/Open
9_chapter 3.pdf1.24 MBAdobe PDFView/Open

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