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Properties and behavior of magnetorheological elastomers and foams
Zedník, Roman ; Macháček, Ondřej (referee) ; Roupec, Jakub (advisor)
This bachelor thesis provides a current overview of magnetorheological foams and elastomers. The structure of individual types of foams and elastomers was discussed here. Various operation modes which are essential for constructing of devices with these materials were explained. Further regulation options and ways of magnetic induction conduction were discussed. And most important microscopic and macroscopic properties were highlighted. Latest ways of production of these materials are mentioned here. Lastly methods of use of MR foams and elastomers were proposed and above that which of the materials is most appropriate for certain application was said.
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Turbocharger Rotors using Rolling Bearings
Šárovec, Marek ; Dlugoš, Jozef (referee) ; Novotný, Pavel (advisor)
The main purpose of this diploma thesis is to design turbocharger rotor using rolling element bearings. The diploma thesis is compiled from two specialized search parts dealing with turbocharger rotor and rolling element bearing computation, respectively. The application of the particular rotor using the multi body system Adams – View is described in the following chapter. In the last chapter, one can find the comparison between rotor using bearing with steal and hybrid ceramic rolling element. Also, there is compariosn between rolling element bearing and journal bearing. In the maximum rotor speed, the decrease of more than 50 % in power loss, due to usage of rolling element bearing, resulted from this comparison.
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Stiffness of Industrial Robot Arm
Vogel, Jan ; Jurčišin,, Miroslav (referee) ; Knoflíček, Radek (advisor)
Stiffness analysis of an arm of an industrial robot with linear kinematics during a drilling operation. For solving this problem are used optical scanners. Finding the optimal cutting force for drilling by criterions: minimal deformation of robots arms and, at the same time, the emerging vibration from the cutting process is also minimal.
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Design of underground garage under the block of flats
Císařová, Kateřina ; Hrubý, Tomáš (referee) ; Klusáček, Ladislav (advisor)
As the main topic this thesis describes the design and evaluation of selected reinforced concrete members of the underground garage construction of the administration building at ultimate limit state and also at serviceability limit state, both in accordance with EC2: Design of Concrete Structures. Designed members in particular are monolithic slab, girders and columns. Structural design and evaluation of other structures of the building are not part of this thesis. The text part of the thesis concerns the descriptions of analysed structures and also the descriptions of the loads acting on them. Method of designing of the structures, methods of calculating of inner forces, and also the method of modelling the structure in software SCIA Engineer are herein further described. The annexes are mainly structural analysis, which expresses the knowledge obtained from the theoretical part of this thesis, and the drawing documentation.
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Lapped scarf joints for reconstruction of historical structures
Kunecký, Jiří ; Fajman, P. ; Hasníková, Hana ; Kuklík, P. ; Kloiber, Michal ; Sebera, V. ; Tippner, J.
This paper presents a description of the repair of timber structures using a prosthesis scarf\njoint designed for the replacement of damaged parts of beams. This new scarf joint makes use\nof the strutting effect of inclined contact faces where the forces are transmitted through\nwooden coupling elements - wooden dowels or keys. The scarf can be modified in four\nvariants according to the relevant stress and is suitable for historically valuable timber\nstructures. It meets both functional and aesthetic requirements. The designer - structural\nengineer will learn in the methods the load bearing capacity or stiffness of the beam with the\ndesigned joint, its recommended dimensions and detailed geometry. The contractor will\nappreciate the description of the execution and maintenance of the joint.
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Optimizing design of the slide CNC horizontal boring machines
Valenta, Tomáš ; Sobola, Radim (referee) ; Marek, Jiří (advisor)
This master's thesis deals with proposals for solutions to increase the stiffness of the slide for CNC horizontal boring standing in order to optimize the design of the slide. Selected problem was solved by sensitivity analysis using desegin of experiment in conditions of linear regression analysis. Data for the sensitivity analysis were obtained by using computational modeling using finite element method. The solution provides a view of the degree of influence on the deformation of the examined elements of the slide. Based on these results were selected elements with the greatest influence and created three ideological designs for improvement. Of these designs, was chose an optimal variant by PATTERN method acoording on the technical, economic and technical-economic aspect. This work offers a new look for the innovating the design to increase rigidity.
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STIFFNESS ANALYSIS OF FRONT PART OF THE VEHICLE
Coufal, Tomáš ; Kovanda, Jan (referee) ; Kohút,, Pavol (referee) ; Vémola, Aleš (advisor)
The thesis deals with the front part stiffness of modern vehicles, especially for the use in the field of forensic engineering in the traffic accident analysis. During the traffic accident analysis, an inquiry into the collision between vehicles is carried out which is an integral part of determining the energy loss of the vehicle at the impact, or more precisely the deformation energy expressed in the form of Energy Equivalent Speed (EES). In case of known stiffness of given part of the vehicle and based on the depth of deformation, it is possible to calculate the deformation energy, or more precisely EES corresponding with given damage of the vehicle. In the field of forensic engineering, the values of stiffness of individual vehicle components are not known and therefore, alternative methods are used to calculate the EES, they are outlined in the research part of this dissertation. However, the current methods of EES determination have some limitations when it comes to usability, and therefore, new EES calculation for the front part of the vehicle was designed in the research. It was based on the real crash test results using real stiffness characteristics of the front part of a vehicle. The front part of the vehicle is divided into individual areas and each of these parts is characterised by its own stiffness coefficient. The designed EES calculation can thus be also used for collisions with partial overlapping, taking into account the real stiffness of the damaged part of the vehicle, which was not possible with existing methods. In the research part of this dissertation, a computer programme to calculate deformation energy and EES was processed. It works with individual stiffness characteristics in given areas where the input data are entered by the user and include the depth of permanent front part deformation in individual areas, vehicle weight, the direction of an impact force and the friction coefficient on the contact surface. Considering the fact that the vehicle stiffness is also one of the control parameters at solving collisions in the PC-Crash simulation programme, which is used in forensic engineering practice for the analysis of a collision process, a supplementary computer programme was designed. Based on the above-mentioned input data, the supplementary programme can further calculate data for collision solving in the simulation programme, namely stiffness, restitution coefficient and the vehicle damage stated in the output report of the simulation programme. Based on these data, the expert thus has the opportunity to solve the collision of two vehicles in the simulation programme with as much preciseness as if it was a real collision.
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Development And Verification Of A New Method For Measuring The Stiffness And Damping Properties Of Joints In Parallel Kinematic Structures
Kolouch, Martin ; Tomáš, Jiří (referee) ; Knoflíček, Radek (advisor)
In this dissertation is presented the development of a new measurement method for the stiffness and damping characteristics of a joint in a parallel kinematic machine tool. The main contribution of this method is specially for applications, that demand accurate information about stiffness and damping parameters from assembled parts of machines tool. Methods for compensation of deformations in machines tool, that are carried out by control, belong to these applications. Another contribution of this work is the technical implementation of the proposed principle of the new method. At this point the focus of the work was devoted to signal processing, that differs in a certain degree from other types of signal processing methods, that are used in other dynamic measurements, e.g. modal analysis. One of the main requirements was the possibility to consider the nonlinear behavior of the measured structure. In another chapter the modified signal processing method was used for measuring a joint in a test rig. The results were compared with results from other measurement methods. On account of this comparison the statement was made that the new method can be used for measuring the stiffness and damping parameters of machine parts. Finally the new method was applied to measure the properties of a joint, which was built in a machine tool. Moreover, the problems, that appeared during the measurement, were also described.
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