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Heating air generator
Hodás, Ladislav ; Čížek, Petr (referee) ; Brandejs, Jan (advisor)
This thesis focuses on design of device to generate hot air. This generator is supposed to be used to perform thermal tests for a company. Introduction summarizes general knowledge about ventilators, heat transport in air flow, and pressure losses. Main part of the thesis describes development of the generator. Initial design was followed by selection of suitable solution variants, design of major parts of the generator supported by calculations and overall conception of the generator. Final part summarizes the achievements and economic analysis.
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FEM analysis of carriage for top drive system of drilling rig and its modification
Plachý, Jiří ; Čížek, Petr (referee) ; Klapka, Milan (advisor)
This diploma thesis deals with FEM analysis and optimization of carriage for top drive system of drilling rig Bentec 350 AC and it is defined as a development contract for company MND Drilling & Services a.s. Intensive drilling leads to damages and repeated occurrence of fatigue cracks on carriage especially along edges of welded ribs in their heat-affected zone. The aim of this thesis is to draft construction improvements of carriage which leads to elimination of damages. Realization of this modifications depends on correct definition of boundary conditions, analysis of damage occurrence as well as verification of carriage drafts with finite element method.
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Design of semiactive seat suspension for agricultural machines
Zindulka, Martin ; Čížek, Petr (referee) ; Strecker, Zbyněk (advisor)
The thesis deals with design of a semiactive seat suspension system for an agriculture machines and design of dynamic model of the system, which includes real parameters of a magnetorheological (MR) damper. The dynamic model is a single degree of freedom model and it is made in program Matlab. In the model, response time of the MR damper and three control algorithms are implemented (two-state Skyhook, Skyhook linear approximation damper control and Acceleration Driven Damper control). Based on the results of the simulations, the damping characteristics are defined, and the MR damper is modified to achieve fast response time. A test seat is designed to test transmission of vibrations to the driver. The simulation results provide a comparison of efficiency of the seat suspension depending on the response time and control algorithm, as well as a comparison with a passive suspension system. On the designed test seat with MR damper with a fast response time, the vibration transmission is reduced up to 25 % compared with the best passive seat suspension setup.
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Design of knee joint simulator
Polnický, Vojtěch ; Čížek, Petr (referee) ; Vrbka, Martin (advisor)
The diploma thesis is focused on the design and realization of an experimental device. The purpose of device is the simulation of dynamic and kinematic conditions of knee replacement during the walking cycle. The simulator will be used to study the formation of the lubricating film in contact of the femoral component and the polyethylene spacer, and to the cyclic wear tests for knee replacements. First part of thesis is focused on the description of working parameters of knee replacements and analysis of knee joint simulators. The description of conceptual design and selection of the final variation follows. The final design allows simulation of dynamic and kinematic conditions of ISO 14 243-3. Creation of lubricating film is analyzed by the non-contact optical fluorescence microscopy method. The work includes complete drawing documentation, wiring diagram, verification of the functionality of the device and detailed operating instructions.
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Draft production line for light transmitting LiCrete blocks
Caletka, Tomáš ; Čížek, Petr (referee) ; Mazal, Pavel (advisor)
The aim of this thesis is to design a production line for manufacturing of light transmitting bricks LiCrete. This brick is a special interior design component which is made of concrete and light transmitting parts. It’s manufactured by casting into the dismountable molds. The research part explains manufacturing technology and possibilities to build production line. The concept solution part is about two concepts of production line and about a few ways how to integrate vibration machine into the line. Main part of the thesis describes mechanical design solution with focus on manipulators and vibration part. Last part of the thesis is about design of automation integration into the production line.
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Mechanical upper limb prosthesis
Koukal, Ondřej ; Čížek, Petr (referee) ; Paloušek, David (advisor)
This thesis elaborates on design and fabrication of an artificial mechanical upper limb prototype for transradial amputations, i. e. for patients with stump between elbow and wrist joints. The artificial limb is designed for use in a wide spectrum of patients. Therefore, the main components are designed to be applicable to smaller as well as larger hand dimensions. The artificial mechanical limb is designed to be controlled by the other hand of a patient and enables grasping of objects via cylindrical and hook grip. Fingers are driven by tension springs and can be locked in extension. Clenching can be initiated by pressing a button, which unlocks the fingers, thus an object can be grasped. Wrist joint is adjustable when pressed a release button. Forearm joint is locked by preloaded spring. The lock of the forearm joint is released by sufficient torque. New position of the forearm joint is locked automatically when the torque is not being applied. Prototypes of the artificial mechanical upper limb were manufactured by using of rapid prototyping technologies (FDM, SLM) as well as CNC milling machine. All parts of the artificial limb were designed with regard to manufacturability by conventional methods such as casting, injection and the like. The artificial limb prototype had been designed on 3D data basis of a specific patient, who already has tested the prototype. Following materials were used on the prototype: ABS plastic, SikaBlock M940 polyurethane, aluminium and 316L stainless steel.
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Excitation device of the physical axle model
Zeman, Petr ; Čížek, Petr (referee) ; Mazůrek, Ivan (advisor)
The main objective of this thesis was to design an excitation device for a full-axle test station for the simulation of a crossing test over bump, used to verify the springing and damping properties of passenger car wheel suspensions. The motivation for the development of the excitation device of the all-axle station was the need to test the properties of the suspension elements in a real scale, and to add a new form of excitation for the axle model that is built in the laboratory of the IMD FME. Until now, this had only one excitation option, a vibration resonator. Firstly, a virtual dynamic axle model was created by crossing an obstacle in Matlab Simulink, which was mainly used to determine the force load exerted by the simulator. The proposed device is divided into a weighing arm and a drive unit. Using the designed device, the obstacle crossing can be simulated with a height of up to 5 cm at a speed of up to 30 km/h and an axle weight of up to 800 kg. The device also records the force exerted from the wheel to the pad throughout and after the excitation. The developed device meets the specified space and modal behaviour requirements, which does not interfere with the force measurement process. The device operates by forcing a cylindrical barrier under the axle wheel and, in conjunction with an existing axle model, forms a crossover test simulator that will be used for the development and experimental verification of automotive suspension components, such as MR dampers in particular.
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Model engine for F4 class aircraft
Čížek, Petr ; Janoušek, Michal (referee) ; Drápal, Lubomír (advisor)
The diploma thesis deals with the construction of two-stroke engine for the propulsion of a scaled aircraft model, which can fall into the category FAI F4. The introduction of this thesis carries out research and familiarization with the category of F4 aircraft. Part of the research is a brief overview of two-stroke and four-stroke variants of model engines, with the fact that more attention is given to the construction details of two-stroke engines. Subsequently, the design and thermodynamic 1-D simulation of the power parameters of the designed engine are carried out, followed by dynamic simulation to verify the lifespan of the engine bearings.
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Resonance and damping behavior of lattice structures produced by Selective Laser Melting
Lagiň, Adam ; Čížek, Petr (referee) ; Koutný, Daniel (advisor)
In reaction to the uptrend of additive manufacturing of lightweight structured metallic parts, this diploma thesis is focused on the resonant and damping behavior of micro-truss lattices produced by Selective Laser Melting (SLM) technology. Micro-truss structures already found usage in various types of optimizations. Therefore, the optimization of resonance or damping could be also assumed as possible. For this purpose, several finite element analysis approaches were used, including the referent solid element model and simplified beam models. Obtained results were verified experimentally via pulse modal analysis. Material and mechanical properties of samples for FEA results and experimental results comparison were unified through secondary experiments. The main goal of this research was to explore the behavior of resonance and damping of structures when their elementary parameters are changed. The results from both, numerical and experimental approaches confirm that the eigenfrequency and the damping ratio of the structure can be affected by the change in the truss diameter, cell size, or type of structure. The work also presents the successful methods for simplified beam model optimization, which guarantees its high precision in the wide field of tested samples. This newly obtained knowledge creates a comprehensive overview of micro-truss structures, which can be used for the conscious design of ultra-light parts with the required eigenfrequency and damping ratio.
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