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The design of fast magnetorheological valves without the use of ferrites
Strmiska, Tomáš ; Růžička, Bronislav (referee) ; Strecker, Zbyněk (advisor)
This diploma thesis deals with development of a new generation of magnetic circuits of fast magnetoreological (MR) dampers that will not use problematic ferrite materials. To ensure a short response time, eddy currents must be avoided. Using the Finite Element Method, 2 solutions were proposed - the use of soft magnetic composites with high electrical resistance and the cutting of grooves in metallic material. Subsequently, 2 magnetic circuits were produced - one from Sintex SMC prototyping material composite and one from 11SMn30 steel with 48 deep grooves 0,35 mm wide. Both were implemented into the MR damper and tested on a hydraulic pulsator. The results of the experiments were compared with 2 different MR dampers: one with 11SMn30 magnetic circuit without grooves and another with the Epcos N87 ferrite magnetic core. It has been found that both new circuits have ensured an equally short response of the damper force to the change of electric current like ferrite. At the same time, a much larger dynamic range was ensured. Compared to 11SMn30 without grooves, the new circuits provided approximately 7x faster response.
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The development of fail-safe magnetorheological damper
Hašlík, Igor ; Růžička, Bronislav (referee) ; Kubík, Michal (advisor)
This diploma thesis deals with an engineering design of a fail-safe magnetorheological (MR) damper capable of semi-active control. The first part of the thesis is devoted to the current state of knowledge of fail-safe MR dampers and permanent magnets contained in these dampers. The next part contains an engineering design of a fail-safe MR damper, made using FEM simulations, and its subsequent testing in terms of magnetic and hydraulic properties. Finally, a design of a fail-safe MR damper with fast response time was made and simulated using verified FEM analysis. Fast response time is ensured by limiting the generation of eddy currents in the piston core by grooving.
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Construction of demagnetizing device of MR dampers for Hyundai
Batelka, Jiří ; Kubík, Michal (referee) ; Strecker, Zbyněk (advisor)
The aim of this thesis in to find a suitable way of demagnetizing MR damper. To achieve this goal, a device based on Arduino DUE was assembled and the effects of adjustable parameters are examinated. Decrease of remanence from original 12 mT before demagnetizing to the resulting 0,23mT was reached. It is possible to use the found effects of adjustable parameters and the device to find suitable ways of demagnetizing other devices.
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Methodology of magnetorheological sport damper demagnetization
Strmiska, Tomáš ; Kubík, Michal (referee) ; Strecker, Zbyněk (advisor)
This thesis is dedicated to discovering the most efficient methods of demagnetization. At the beginning, basics of magnetorheological (MR) dampers are explained. Available literature is studied to propose appropriate methods of demagnetization. An apparatus is designed and utilized to research methods of MR damper piston and magnetic circuit of MR viscometer demagnetization. The outcome of this work is analysis of recorded data including impact analysis of all identified parameters. The best demagnetization methods are described.
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The development of fail-safe magnetorheological damper
Hašlík, Igor ; Růžička, Bronislav (referee) ; Kubík, Michal (advisor)
This diploma thesis deals with an engineering design of a fail-safe magnetorheological (MR) damper capable of semi-active control. The first part of the thesis is devoted to the current state of knowledge of fail-safe MR dampers and permanent magnets contained in these dampers. The next part contains an engineering design of a fail-safe MR damper, made using FEM simulations, and its subsequent testing in terms of magnetic and hydraulic properties. Finally, a design of a fail-safe MR damper with fast response time was made and simulated using verified FEM analysis. Fast response time is ensured by limiting the generation of eddy currents in the piston core by grooving.
|
|
|
Construction of demagnetizing device of MR dampers for Hyundai
Batelka, Jiří ; Kubík, Michal (referee) ; Strecker, Zbyněk (advisor)
The aim of this thesis in to find a suitable way of demagnetizing MR damper. To achieve this goal, a device based on Arduino DUE was assembled and the effects of adjustable parameters are examinated. Decrease of remanence from original 12 mT before demagnetizing to the resulting 0,23mT was reached. It is possible to use the found effects of adjustable parameters and the device to find suitable ways of demagnetizing other devices.
|
|
|
The design of fast magnetorheological valves without the use of ferrites
Strmiska, Tomáš ; Růžička, Bronislav (referee) ; Strecker, Zbyněk (advisor)
This diploma thesis deals with development of a new generation of magnetic circuits of fast magnetoreological (MR) dampers that will not use problematic ferrite materials. To ensure a short response time, eddy currents must be avoided. Using the Finite Element Method, 2 solutions were proposed - the use of soft magnetic composites with high electrical resistance and the cutting of grooves in metallic material. Subsequently, 2 magnetic circuits were produced - one from Sintex SMC prototyping material composite and one from 11SMn30 steel with 48 deep grooves 0,35 mm wide. Both were implemented into the MR damper and tested on a hydraulic pulsator. The results of the experiments were compared with 2 different MR dampers: one with 11SMn30 magnetic circuit without grooves and another with the Epcos N87 ferrite magnetic core. It has been found that both new circuits have ensured an equally short response of the damper force to the change of electric current like ferrite. At the same time, a much larger dynamic range was ensured. Compared to 11SMn30 without grooves, the new circuits provided approximately 7x faster response.
|
|
|
Methodology of magnetorheological sport damper demagnetization
Strmiska, Tomáš ; Kubík, Michal (referee) ; Strecker, Zbyněk (advisor)
This thesis is dedicated to discovering the most efficient methods of demagnetization. At the beginning, basics of magnetorheological (MR) dampers are explained. Available literature is studied to propose appropriate methods of demagnetization. An apparatus is designed and utilized to research methods of MR damper piston and magnetic circuit of MR viscometer demagnetization. The outcome of this work is analysis of recorded data including impact analysis of all identified parameters. The best demagnetization methods are described.
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