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Magnetoreologický tlumič pro formuli Student
Dlápal, Václav ; Strecker, Zbyněk (oponent) ; Mazůrek, Ivan (vedoucí práce)
Diplomová práce se zabývá návrhem, výrobou a testováním funkčního vzorku magnetoreologického tlumiče pro vozidlo kategorie Formule Student. Cílem bylo navrhnout a otestovat tlumič s obdobnými tlumicími vlastnostmi, jako má konvenční tlumič na zvoleném vozidle. Návrhové tlumicí charakteristiky tlumiče byly stanoveny pomocí čtvrtinového modelu vozidla a vyhodnoceny srovnáním dosažených minimální přítlačný sil pneumatiky. Porovnávány byly charakteristiky konvenčního a navrhovaného tlumiče. Dále je uvedena pevnostní kontrola navržených dílů, hydraulická a statická magnetická analýza. V práci je také popsána výroba specifického dílu magnetoreologického tlumiče – pístu. Vyrobený funkční vzorek byl otestován a naměřené tlumicí charakteristiky byly podrobně analyzovány.
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Magnetorheological Suspension Damper for Space Application
Kubík, Michal ; Porteš, Petr (oponent) ; dr hab. inż. Janusz Gołdasz, prof. PK (oponent) ; Mazůrek, Ivan (vedoucí práce)
The present thesis deals with the development of the MR suspension damper for space application. Some important requirements for semi-active control damper for space application are a hermetic separation of operating fluids from the rest of the launch vehicle and short response time of damping element. Those requirements meet magnetorheological damper with bellows unit, according to state of the art. Magnetic circuit of the MR damper was made from ferrite material which allows to rapidly decrease the response time of the MR damper. Hermeticity was ensured using a bellows unit. Design of this type of damper exhibits a lot of design limitations. The developed MR damper with ferrite magnetic circuit achieved response time 4.1 ms and dynamic force range 8. During the design of the MR damper for space application, a new method for design of semi-actively control MR damper with short response time were searched. Specifically, the method for elimination of eddy currents in magnetic circuit of MR damper, magnetostatic and transient magnetic model, CFD model of bypass gap, hydraulic model of MR damper and their experimental verification. The presented methods allow for the design new MR damper for space application lighter, with short response time and with higher dynamic force range.
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Magnetoreologický tlumič pro formuli Student
Dlápal, Václav ; Strecker, Zbyněk (oponent) ; Mazůrek, Ivan (vedoucí práce)
Diplomová práce se zabývá návrhem, výrobou a testováním funkčního vzorku magnetoreologického tlumiče pro vozidlo kategorie Formule Student. Cílem bylo navrhnout a otestovat tlumič s obdobnými tlumicími vlastnostmi, jako má konvenční tlumič na zvoleném vozidle. Návrhové tlumicí charakteristiky tlumiče byly stanoveny pomocí čtvrtinového modelu vozidla a vyhodnoceny srovnáním dosažených minimální přítlačný sil pneumatiky. Porovnávány byly charakteristiky konvenčního a navrhovaného tlumiče. Dále je uvedena pevnostní kontrola navržených dílů, hydraulická a statická magnetická analýza. V práci je také popsána výroba specifického dílu magnetoreologického tlumiče – pístu. Vyrobený funkční vzorek byl otestován a naměřené tlumicí charakteristiky byly podrobně analyzovány.
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Magnetorheological Suspension Damper for Space Application
Kubík, Michal ; Porteš, Petr (oponent) ; dr hab. inż. Janusz Gołdasz, prof. PK (oponent) ; Mazůrek, Ivan (vedoucí práce)
The present thesis deals with the development of the MR suspension damper for space application. Some important requirements for semi-active control damper for space application are a hermetic separation of operating fluids from the rest of the launch vehicle and short response time of damping element. Those requirements meet magnetorheological damper with bellows unit, according to state of the art. Magnetic circuit of the MR damper was made from ferrite material which allows to rapidly decrease the response time of the MR damper. Hermeticity was ensured using a bellows unit. Design of this type of damper exhibits a lot of design limitations. The developed MR damper with ferrite magnetic circuit achieved response time 4.1 ms and dynamic force range 8. During the design of the MR damper for space application, a new method for design of semi-actively control MR damper with short response time were searched. Specifically, the method for elimination of eddy currents in magnetic circuit of MR damper, magnetostatic and transient magnetic model, CFD model of bypass gap, hydraulic model of MR damper and their experimental verification. The presented methods allow for the design new MR damper for space application lighter, with short response time and with higher dynamic force range.
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The role of sonication of polyethyleneoxide solutions containing magnetic nanoparticles on morphology of nanofibrous mats
Peer, Petra ; Stěnička, M. ; Filip, Petr ; Pizúrová, Naděžda ; Babayan, V.
Properties of the resulting polymer nanofibers are often tailored by sonication technique applied prior or past an electrospinning process. The aim of this contribution is to evaluate morphology of nanofibrous mats formed by poly(ethylene oxide) with distributed magnetic nanoparticles (MNP) (about 20 nm in diameter) in dependence on time of sonication of the used polymer solutions. The solutions were exposed to sonication (intensity 200W, frequency 24 kHz) for 10, 30, and 60 minutes. It was shown that rheological characteristics (viscosity, storage and loss moduli) strongly depend on time of sonication (particularly phase angle) in contrast to electric conductivity and surface tension. For analysis of homogeneous distribution of MNP in polymer solution, the rheological measurements were carried out also in presence of external magnetic field. Magnetorheological efficiency (a relation of corresponding viscosities) was determined for 80, 170, and 255 mT. Consequently, changed rheological characteristics participate significantly in the process of electrospinning and resulting quality of the obtained nanofibrous mats. Qualitative changes were described by\nmeans of scanning electron microscopy (variance of mean diameter of nanofibers), transmission electron microscopy (distribution of MNP within nanofibrous mats). Static magnetic properties were determined by a vibration sample magnetometer. It was shown that even distribution of MNP in the mats can be achieved by mere sonication process without application of external magnetic field during an electrospinning process. However, time of sonication generates a degree of embedding of MNP into individual nanofibers.
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