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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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Enhancing of sedimentation stability using bentonit based clays
Michal, Lukáš ; Vimmr, Jan (referee) ; Roupec, Jakub (advisor)
The diploma thesis is focused on the issue of sedimentation stability of magnetorheological fluids, whis represents one of the most important characteristics determining the reliability of these fluids. Higher sedimentation stability can by achieved in several ways. Methods that are further examined in the thesis include particle polymerization and the addition of clay mineral additives. Both achieve positive results by schowing increased sedimentation stability. However, in the case of additives, the effect is much higher. In particular, the CLAYTONE 40 additive achieves a lower particle sedimentation rate while maintaining the same viscosity as the commercial LORD-122ED. The results provide significant knowledge in the field and can bring magnetorheological fluids closer to wider commercial use.
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Tribological characteristics of smart fluids
Michalec, Michal ; Čermák, Jan (referee) ; Svoboda, Petr (advisor)
The master's thesis deals with experimental study of tribological characteristics of smart fluids. Smart fluids are substances in liquid state reacting to the presence of magnetic or electric field by change in rheological properties. For possible application in devices using conventional lubricants is necessary to choose suitable smart fluid and study the influence of excitation on formation of lubricating layer, friction and wear. Comprehensive description of excitation influence is executed using three experimental devices and theoretical model for measurements parameters specification. Assessed are lubricant film thickness, friction coefficient and wear under smart fluid activation in non-conformal contact. Results show significant observable influence of smart fluids excitation on all assessed aspects. Understanding the mechanisms of smart fluids excitation can be a key step in development of intelligent devices with active external control of lubricant behaviour and character, that could lead to maintenance cost reduction and effectivity improvement.
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Hydraulic shock absorbers of train bogie
Odehnal, Lukáš ; Jeniš, Filip (referee) ; Kubík, Michal (advisor)
This bachelor thesis mainly deals with design solutions of adaptive dampers used on railway vehicle bogies. The first part gives a general overview of the topic. The main part discusses current designs of adaptive dampers that have already been tested. Final part of the thesis compares the designs including their determining parameters in order to obtain a large enough sample to contribute to the development of a new, electronically controlled damper at the VUT in Brno.
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Durability test of magnetorheological fluid at high temperature
Grygárek, David ; Strecker, Zbyněk (referee) ; Roupec, Jakub (advisor)
This bachelor’s thesis is focused on behaviour of magnetorheological fluid during the durability test. In the first part are described basic properties of MR fluid and is defi-ned parameter LDE (Lifetime Dissipated Energy), which is used for prediction of durability of MR fluid. Primary part of thesis devote to realization of experiment, which measures a part of durability test at 70°C and monitoring the yield stress, vis-cosity and residual magnetism.
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Testing of automotive sport suspension
Čípek, Pavel ; Růžička, Bronislav (referee) ; Strecker, Zbyněk (advisor)
The diploma thesis deals with testing of sports car suspension. The aim is the testing of fast magnetorheological damper in semiactive suspension that corresponds to quarter car model. The fast magnetorheological damper has a response time 2 ms. If the response time is short enough (order of units miliseconds) it is possible (based on earlier simulations) to achieve improvement of driving safety (better stability of force of tyre on roadway) and comfort (reduction of vibrations). The thesis proves this statement with series of experiments.
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The design survey of magnetorheological dampers
Tran, Adam ; Macháček, Ondřej (referee) ; Kubík, Michal (advisor)
Bachleor´s thesis deals with the damping systems such as magnetorheological dampers or magnetorheological valves. At beginning MR effect is described in MR devices. Next part deals with the designs, materials, characteristics of FEM models e.g. magnetic inductions, tested characteristics (F-v, time response), and used MR fluids in MR devices. In second part there are compared each MR device (MR damper or MR valve) in listed characteristics from previous part and describes issues, which are not in publications.
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Design of fail-safe magnetorheological damper
Hašlík, Igor ; Novák, Petr (referee) ; Kubík, Michal (advisor)
This Bachelor’s thesis deals with an engineering design of so-called fail-safe system applied to a magnetorheological damper. In the beginning there is mentioned an essential knowledge needed for developing of such a device. The following part shows some of the current designs. Next part consists of few concept designs. One of those concepts was chosen to be processed in the engineering part. Finally a simplified magnetic and hydraulic model of the final design is calculated.
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The study of sedimentation of MR fluids for space applications
Vančurová, Martina ; Strecker, Zbyněk (referee) ; Roupec, Jakub (advisor)
This bachelor thesis deals with experimental determination of the effect of iron particle size on the sedimentation rate of magnetorheological (MR) fluids. MR fluids from three producers are examined here: Liquids Research Limited (Great Britain), HaoHua (China) a LORD Corporation (USA). Particles describing the effect of MR fluids’ different attributes on their sedimentation are summarized in an overview of current knowledge. The development of the Matlab script, that detects and measures the size of particles in the input electron microscope images, is presented. The particles are also measured manually in some images, which is partly used as a reference measurement for the developed script. The particle size measurement results are then compared with the sedimentation behavior of examined MR fluids.
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Enhancing of sedimentation stability using bentonit based clays
Michal, Lukáš ; Vimmr, Jan (referee) ; Roupec, Jakub (advisor)
The diploma thesis is focused on the issue of sedimentation stability of magnetorheological fluids, whis represents one of the most important characteristics determining the reliability of these fluids. Higher sedimentation stability can by achieved in several ways. Methods that are further examined in the thesis include particle polymerization and the addition of clay mineral additives. Both achieve positive results by schowing increased sedimentation stability. However, in the case of additives, the effect is much higher. In particular, the CLAYTONE 40 additive achieves a lower particle sedimentation rate while maintaining the same viscosity as the commercial LORD-122ED. The results provide significant knowledge in the field and can bring magnetorheological fluids closer to wider commercial use.
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