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Limiting and Degradation Processes of Magnetorheological Suspension Dampers
Roupec, Jakub ; Bauer, František (referee) ; Ondrůšek, Čestmír (referee) ; Dobeš, Petr (referee) ; Mazůrek, Ivan (advisor)
This work deals with the research of degradation of magnetorheological (MR) fluid during long-term loading under conditions that correspond to the real load in the linear MR devices such as dampers. The behaviour of MR fluid is described by a Bingham model of viscoplastic fluid. The parameters of this model are the yield stress and viscosity. Their values are determined by the shear rate from 1 to 2,8104 s-1. Results of durability tests show a significant decrease in viscosity of MR fluid, a gradual increase in yield stress in the off-state and a significant decrease in MR effect. The paper also described the effect of temperature on these parameters and there is also designed a method of non-assembly diagnostic of the MR fluid state in the damper using the "rate of pulsation."
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Megnetorheological shockabsorber
Lazar, Jaroslav ; Růžička, Bronislav (referee) ; Mazůrek, Ivan (advisor)
This master's thesis deals with an engineering design of an external reservoir for hydraulic shock absorbers with combined filling of oil and magnetorheological fluid. The first part describes existing designes of magnetorheological shock absorbers and characteristics of magnetorheological fluid. Next part describes a design of an experimental external reservoir and a test of its functionality on a prototype. This is followed by an optimalized engineering design of the experimental external reservoir.
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Sedimentation of MR fluid at the start of new space lanucher
Berka, Pavel ; Strecker, Zbyněk (referee) ; Roupec, Jakub (advisor)
This bachelor thesis deals with sedimentation behavior of magnetorheological fluid exposed to acceleration 1-6 G. That simulates start of a space launcher. Main goal of this work is to bring new knowledge of MR fluids behavior. Experiment of accelera-ted sedimentation as well as the long term sedimentation is presented, including new method and measuring device developed to measure the sedimentation, in order to compare different commercial MR fluids. Results from this work will be used in development of the new semiactive dum-ping system for carrying load in ESA new space launcher.
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Test of remanency in a sport damper in dependence on a material of magnetic circuit
Polášek, Jan ; Kubík, Michal (referee) ; Roupec, Jakub (advisor)
This bachelor’s thesis deals with testing of maximal magnetic induction, remanence and B-H curve of different kinds of steels and application of this knowledge when choosing materials for magnetic circuit of magnetorheological (MR) dampers. The introduction of the thesis is intended to analyse knowledge of magnetorheological fluids and magnetic characteristics of different kinds of materials. Another part of bachelor’s thesis deals with the choice of steels of different chemical composition, heat treatment of steel, testing and comparing with FEM results. The aim of the thesis is also to design a clamping device for testing of magnetic circuit and to describe used measuring instruments and measurement methodology too.
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Hydrodynamic dampers on the principle of magnetic fluid
Přikryl, Matěj ; Himr, Daniel (referee) ; Pochylý, František (advisor)
This bachelor's thesis deals with damping vibrations emerging due to the movement of a vehicle. The first section provides an overview of contemporary types of dampers with thorough explanation of the principle of hydrodynamic damper. This section also contains simulation of vibrating vehicle equipped with passive damper. Literature research of magnetic fluids and description of magnetoviscous phenomenon is presented in the second part, which freely continues to the topic of magnetorheological (MR) dampers. The final chapter firstly describes current hydrodynamic dampers based on squeeze film (SF) mode of magnetorheological fluid and at the conclusion the author's concept of SF MR damper is submitted.
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Design of Low-Pressure Piston Rheometer
Lán, Radek ; Strecker, Zbyněk (referee) ; Roupec, Jakub (advisor)
This thesis is focused in design of Low-Pressure Piston Rheometer intended for experimental identifying of magneto-rheologic (MR) liquid properties at long-term load. MR liquid is briefly introduced in the initial part of the thesis. There follows a search related to way of liquids properties measurement and overview of MR dampers which are close to piston rheometers by their construction. MR dampers with through piston-rod have been emphasised. The second part of the thesis is focused on calculation of magnetic circuit of the rheometer throttle leak. The rheometer is designed in the last part of the thesis.
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Optimization of the existing construction of magnetorheological clutch
Bedřich, Miroslav ; Růžička, Bronislav (referee) ; Roupec, Jakub (advisor)
This work deals with the reconstruction of magnetorheological (MR) clutch. The extensive research on the use of magnetorheological technology in practice was developed in the first part. The function of MR dampers, MR brakes and MR clutches were described. Some parameters of MR clutches were listed and compared. The second part concentrates on construction modifications to improve some parameters of MR clutch. The experiments verifying improvement of operating parameters of MR clutch were carried out in the third part.
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Production technology of Magnetorheological fluids
Nováček, Vladislav ; Mazůrek, Ivan (referee) ; Roupec, Jakub (advisor)
The thesis deals with the overview over the current knowledge at the field of magnetorheological (MR) fluids. It includes definition of basic characteristics of MR fluids and technological aspects in production of the most important particles and carrier fluids. The aim of the thesis is to describe technological methods used in MR fluids production that can be used for different purposes at BTU. Finally, the thesis tries to estimate possible ways in MR fluids development in the future.
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