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Magnetorheological Strut for Vibration Isolation System of Space Launcher
Macháček, Ondřej ; Borin, Dmitry (oponent) ; dr hab. inż. Janusz Gołdasz, prof. PK (oponent) ; Mazůrek, Ivan (vedoucí práce)
The dissertation thesis deals with the design of magnetorheological (MR) strut for vibration isolation system (VIS) of the launch vehicle. Previously used VIS and their struts are described in state of the art. Each of the struts which contained any fluid was sealed by static seals and elastic bellows made of steel. The strut of a passive system called ELVIS was chosen as an inspiration and therefore analysed thoroughly. The strut is three-parametric that means the damper is elastically connected. The stiffness of this connection is identical to the projection of bellows volumetric stiffness into the axial direction which is called the pressure thrust stiffness. The method of the pressure thrust stiffness determination from the bellows dimensions is presented in the thesis. Moreover, the parameters which can be used for the modification of the ratio between axial and pressure thrust stiffness of bellows is also discussed. This ratio affects the dynamic behaviour of the strut, thus also the behaviour of whole VIS. The multi-body model of VIS based on the Stewart platform mechanism and detailed multi-body model of a single strut was created for the prediction of their dynamic behaviour in a vibration environment. Simulations have revealed the parameters which affect the efficiency of the MR strut: the time response and the dynamic force range of the MR valve. The range of these parameters which should ensure an effective vibration isolation by the MR strut in the specific VIS was determined by the multi-body model; specifically, time response: 0-5 ms and the dynamic force range 5-10. The final design of the MR strut for the VIS of the launch vehicle preceded the design, manufacture and testing of the experimental strut. The parameters of the experimental strut were measured and consequently used for the verification of models used in the thesis. Knowledge obtained during the tests were used in the final design of the strut. One of the most important detections was that the ferrite (material used in the magnetic circuit) cracked during the semi-active control of the experimental strut. Therefore, a method of the fast magnetic circuit designing was established and subsequently patented. The method is based on a shape modification of the magnetic circuit which ensures shorter time response and the magnetic circuit is manufactured by 3D printing. The MR strut designed in this thesis has a predicted time response of 1.2 ms and dynamic range 10. The method which was used for the design process is summarised in conclusions.
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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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Magnetorheological Strut for Vibration Isolation System of Space Launcher
Macháček, Ondřej ; Borin, Dmitry (oponent) ; dr hab. inż. Janusz Gołdasz, prof. PK (oponent) ; Mazůrek, Ivan (vedoucí práce)
The dissertation thesis deals with the design of magnetorheological (MR) strut for vibration isolation system (VIS) of the launch vehicle. Previously used VIS and their struts are described in state of the art. Each of the struts which contained any fluid was sealed by static seals and elastic bellows made of steel. The strut of a passive system called ELVIS was chosen as an inspiration and therefore analysed thoroughly. The strut is three-parametric that means the damper is elastically connected. The stiffness of this connection is identical to the projection of bellows volumetric stiffness into the axial direction which is called the pressure thrust stiffness. The method of the pressure thrust stiffness determination from the bellows dimensions is presented in the thesis. Moreover, the parameters which can be used for the modification of the ratio between axial and pressure thrust stiffness of bellows is also discussed. This ratio affects the dynamic behaviour of the strut, thus also the behaviour of whole VIS. The multi-body model of VIS based on the Stewart platform mechanism and detailed multi-body model of a single strut was created for the prediction of their dynamic behaviour in a vibration environment. Simulations have revealed the parameters which affect the efficiency of the MR strut: the time response and the dynamic force range of the MR valve. The range of these parameters which should ensure an effective vibration isolation by the MR strut in the specific VIS was determined by the multi-body model; specifically, time response: 0-5 ms and the dynamic force range 5-10. The final design of the MR strut for the VIS of the launch vehicle preceded the design, manufacture and testing of the experimental strut. The parameters of the experimental strut were measured and consequently used for the verification of models used in the thesis. Knowledge obtained during the tests were used in the final design of the strut. One of the most important detections was that the ferrite (material used in the magnetic circuit) cracked during the semi-active control of the experimental strut. Therefore, a method of the fast magnetic circuit designing was established and subsequently patented. The method is based on a shape modification of the magnetic circuit which ensures shorter time response and the magnetic circuit is manufactured by 3D printing. The MR strut designed in this thesis has a predicted time response of 1.2 ms and dynamic range 10. The method which was used for the design process is summarised in conclusions.
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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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