京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22704号 / 工博第4751号 / 新制||工||1743(附属図書館) / 京都大学大学院工学研究科建築学専攻 / (主査)教授 池田 芳樹, 教授 西山 峰広, 准教授 聲高 裕治 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

The aim of this thesis is the innovation of the testing device which is located in Institute of Machine and Industrial Design laboratory. The innovation relates to the portal construction design, where will be placed the hydraulic pulsator from the company INOVA Praha Ltd. New portal construction will be designed with respect to specified parameters and requirements and also with regard to the performed tests (damper tests, vibroizolated properties magnetorheological valves tests etc.). The thesis contains detailed analysis of the current tester and detailed analysis of similar machines with focusing on the portal structure and ways of positioning the crossmember. Further parts of the thesis is a detailed description of the design solution, including the computational simulations, attached drawing documentation and experimentally verified functional sample (crossmember).

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.

Disertační se práce se zabývala vývojem magnetoreologického (MR) tlumiče odpružení pro kosmonautiku. Dle současného stavu poznání jsou důležitými parametry pro semi-aktivně řízený tlumič pro kosmonautiku hermetické oddělení pracovní kapaliny od zbytku nosiče a krátká časová odezva tlumícího elementu. Těmto požadavkům vyhovuje magnetoreologický tlumič s vlnovcovou jednotkou. Magnetický obvod MR tlumiče pro kosmonautiku byl vyroben z feritového materiálu, který umožnil výrazně snížit časovou odezvu. Hermetičnost byla zajištěna použitím vlnovcové jednotky. Konstrukce takového typu tlumiče ovšem přináší celou řadu problémů. Vyvinutý MR tlumič s feritovým magnetickým obvodem dosahoval časové odezvy 4.1 ms a dynamického rozsahu 8. Během konstrukčních prací na MR tlumiči pro kosmonautiku byly hledány nové metody pro konstrukci semi-aktivně řízeného MR tlumiče s krátkou časovou odezvou. Konkrétně se jednalo o metodu eliminace vířivých proudů v magnetickém obvodu MR tlumiče, magnetostatický a transietní magnetický model, CFD model obtokové štěrbiny, hydraulický model MR tlumiče a jejich experimentální verifikace. Tyto nové metody umožní konstrukci MR tlumiče pro kosmonautiku lehčí, s nižší časovou odezvou a vyšším dynamickým rozsahem.

The diploma thesis deals with the development of the magnetic circuit of Magnetoreological (MR) dampers with a short time response. To achieve a short response time, a shape approach was chosen whereby the geometry of the magnetic circuit was chosen to significantly eliminate the occurrence of eddy currents. The influence of structures on magnetic properties was first examined on a simpler toroidal core and then the optimization was subjected to the magnetic circuit of the MR damper itself. Geometry optimization was done using FEM simulations. The resulting geometry was made of pure iron using Selective Laser Melting technology (SLM). In addition, a MR damper was completed and its properties on air and with MR fluid were measured, which were then compared with previously developed rapid MR dampers. It has been found that the newly designed magnetic circuit achieves similar time responses as all other compared fast MR dampers and reaches a higher dynamic range than most of the compared variants. The proposed magnetic circuit also has a significantly reduced weight.

This thesis deals with the examination of damper characteristics and influence of individual parameters on vehicle handling, primarily with the use of computer program Matlab Simulink.

The master thesis deals with computational modeling of a turbocharger vibrations and and assessment of influnce of passive dynamic vibration absorber on vibrations of actuator bracket. The use of dynamic vibration absorber was summarized in the research study. The analysis were performed using finite element method in ANSYS. Several computational models of turbocharger were created with different ways of modeling bolted joints between turbocharger parts. Modal analysis of each model was performed and the results were compared. For the selected model, the response to the kinematic excitation from the internal combustion engine for two load conditions was calculated using harmonic analysis. A simple model of vibration dynamic absorber was applied to the turbocharger model with reduced degrees of freedom and its influnce on vibrations of actuator bracket was investigated. Significant decrease of the maximum acceleration amplitude was achieved in a given frequency range when absorber parameters were optimized.

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.

Master 's thesis deals with design of a drivetrain of six cylinder inline engine with cylinder deactivation for heavy agricultural vehicles. In this thesis were devised various possibilities of crankshaft balancing, the best design solution of counterweight was based on optimization in software Catia. Further, the crankshaft was analysed for force and momentum loading and torsional vibration, based on which, the torsional vibration damper was designed. There were considered several options for cylinder deactivation, which were analysed for finest run of engine and the best thermal distribution. Based on these criteria, the best option was to deactivate 2nd and 5th cylinder. The crankshaft was analysed for the fatigue failure by finite element method. The fatigue failure is the most dangerous case for the crankshaft, the resulting safety factor for this limit state is 3,05.

In this diploma thesis is created a cranktrain model in the MBS system ADAMS Engine. The thesis defines basic parameters and proportions of the torsional damper for in-line 5-cylinder engine. This thesis also puts mind to calculation of torsional vibration. In the MBS system ADAMS Engine is demonstrated affect of torsional damper on the torsional vibration of the crankshaft.