National Repository of Grey Literature 49 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Design of paddle shifts for formula student
Dugas, Martin ; Vrána, Radek (referee) ; Koutný, Daniel (advisor)
This bachelor thesis concerns design of paddle shifters for Formula Student. It deals in theoretical part with knowledge of today’s shifting mechanisms, additive manufacturing technologies and ways of weight optimization of parts. In design section, it covers with actual solutions of this problems, whereas the most important target was to minimalize mass and maximize stiffness of the whole mechanism.
Effect of layer thickness on critical angle of additively manufactured lattice structures
Nosek, Jakub ; Vrána, Radek (referee) ; Vaverka, Ondřej (advisor)
Aim of this work is to describe the effect of a layer thickness on critical angel of a lattice structures manufactured by SLM technology. The effect of layer thickness was investigated on single struts and on lattice structures made from stainless steel 316L. Better geometrical accuracy could be obtained, if the smaller layer thickness is used. Less attached powder particles on downskins was also observed on lattice structures. Thanks to this thesis, it is possible to determine, if it is meaningful to decrease the layer thickness in order to improve manufacturability of lattice structures even with higher manufacturing time.
STUDY OF ENERGY ABSORPTION IN MICRO – STRUT LATTICE STRUCTURE PRODUCED BY SELECTIVE LASER MELTING
Vrána, Radek ; Schleifenbaum, Johannes (referee) ; Skalon, Mateusz (referee) ; Paloušek, David (advisor)
Předložená dizertační práce je součástí většího výzkumného projektu, který si klade za cíl využití mikro prutové konstrukce vyrobené technologií SLM jako absorbér rázové energie s přesně navrženými vlastnostmi. Hlavním cílem práce je vývoj numerického modelu deformačního chování mikro-prutové konstrukce vyrobeného technologií Selective Laser Melting (SLM) z materiálu AlSi10Mg. Aby bylo možné dosáhnout hlavního cíle dizertační práce, bylo nutné analyzovat vliv procesních parametrů technologie SLM na tvorbu vnitřních materiálových vad a drsnost povrchu při výrobě mikro-prutové konstrukce. Tyto imperfekce degradují její mechanické vlastnosti a jejich odstranění zlepší možnosti a přesnost numerické predikce. Výsledky ukazují významný vliv dvou hlavních parametrů – skenovací rychlosti laseru a výkonu laseru. Na základě těchto poznatků byly dále definovány parametry vstupní energie Ein a lineární energie Elin, které zahrnují oba zmíněné parametry a byly definovány jejich limitní hodnoty pro minimalizaci vzniklých imperfekcí. Deformační chování vyrobené mikro-prutové konstrukce bylo analyzováno na navrženém pádové zařízení, které umožňuje testování s dopadovou energií až 120 J. Deformační chování je vyhodnocováno s využitím obrazové analýzy záznamu vysoko rychlostní kamery a silového průběhu z tenzometru. Výsledky analýzy byly využity pro validaci numerického modelu v programu ANSYS Explicit, do kterého byly implementovány poznatky o reálném tvaru vyrobeného mikro-prutového materiálu ve formě eliptického modelu geometrie a informace o reálných mechanických vlastnostech ve formě vyvinutého materiálového modelu. Výsledné porovnání výsledků experimentu s predikcí numerického modelu ukazují dobrou shodu v místě maximálního zatížení Fmax (odchylka 5 %) i průběhu celé deformace vzorku. Tyto poznatky budou v budoucnu využity při návrhu absorbéru energie s definovanými mechanickými vlastnostmi.
3D Lattice Structures for Application in Selective Laser Melting technology
Červinek, Ondřej ; Škaroupka, David (referee) ; Vrána, Radek (advisor)
Additive technologies allow manufacturing of components with very complex shapes which are difficult to manufacture with conventional technologies. Among these technologies belongs the Selective Laser Melting (SLM). Suitable applications of SLM include manufacturing of light-weight 3D structures like lattice structure or an organic geometry called gyroid. This bachelor thesis is focused on creation of models of gyroid structure and its application to parts followed by manufacturing with SLM. Series of models were made with mathematical software. Implicitly defined equation were used for better geometry coordination of created models. Options utilization and manufacturability of gyroid structures were tested within application into turbocharger impeller. At the end of this thesis was successfully manufactured the impeller including two types of gyroid structure (single-gyroid and double-gyroid)
Development of 3D metal printing process parameters for producing of the lattice structure
Jaroš, Jan ; Koutný, Daniel (referee) ; Vrána, Radek (advisor)
Selective laser melting (SLM) in additive technology, which allows production of lattice structures. Lattice structures are very difficult to produce using conventional methods. The main use of lattice structures is in aerospace industry and medicine for bone implants production. In this work influence of processing parameters (laser power, scanning speed) on properties (diameter, surface roughness, porosity) of struts is investigated. The processing parameters selection was based on single tracks test. In the first test, ImageJ was used to determine porosity of struts. In the second test porosity was analyzed with more accurate µCT technology. Both tests used 3D scanning technology to determine dimension accuracy and surface roughness of samples. The measurement results led to the detection of processing parameter „window“ where samles had the best combination of surface roughness and porosity. The best results were achieved with 225-275 W laser power and scanning speed of 1400-2000 mm·s-1.
Comparison of micro-lattice structures for energy absorption
Koban, Tomáš ; Vrána, Radek (referee) ; Červinek, Ondřej (advisor)
Additively manufactured metal micro-structures have great potential in energy absorption applications. The recent research in this field led to a much better understanding of failure behaviour of these micro-structures. This thesis focuses on comparison of energy absorption ability of strut-based micro-lattice structures manufactured by selective laser melting depending on their topology and basic material. Energy absorption of three types of lattice structures (BCC, BCCZ, GBCC) made from stainless steel 316L and aluminium alloy AlSi10Mg was examined. Specific energy absorption was used to compare the two materials. The results show that micro-lattice structures made from stainless steel outperform the aluminium ones in energy absorption ability. The highest amount of absorbed energy was measured for BCCZ structure. This thesis describes the failure mechanism of micro-lattice structures and offers a complex evaluation of energy absorption for both materials.
Parametric model of injection mold
Tomanec, Pavel ; Vrána, Radek (referee) ; Brandejs, Jan (advisor)
This bachelor thesis is concerned with creating parametric model of plates injection mold for plastic by using software CatiaV5. It is used for faster and more efficient in the design of the injection mold. The first section describes the basic design and technological elements for designing injection molds. The second part describes the system for creating and constrain the parameters finally verify the functionality of the created model.
Development of the Impact Energy Absorber Made by Metal 3D Printing
Kraicinger, Vít ; Malý, Martin (referee) ; Vrána, Radek (advisor)
Today, variously profiled parts are mainly used for energy absorption. For special cases, precise components are designed, as in the case of Formula Student, where a deformation article with a honeycomb structure is used. This bachelor thesis is focused on the design of an impact energy absorber made by SLM technology and lattice structures. For the design itself, a comprehensive overview of current knowledge in the field of deformation zones, energy absorbers and researches dealing with energy absorption was created. Based on the study, the most suitable material to produce AlSi10Mg was selected. Subsequently, the appropriate type of grid (BCC) and all parameters of the lattice structure were determined. Two energy absorbers with different struts diameters (0.4 mm and 0.8 mm) and different grid sizes (4 mm and 8 mm) were modeled for the selected parameters. At the end of the work are two simplified calculations that show the predicted final values of the proposed absorbers and the stiffness of the layers of the lattice structure with graded density.
Numerical model of lattice structure under dynamic loading made by Selective Laser Melting technology
Červinek, Ondřej ; Maňas, Pavel (referee) ; Vrána, Radek (advisor)
For the purpose of mechanical impact energy absorption in the transport industry are mainly used special profile absorbers. For highly specialized applications is required to use components that are designed for specific kind of deformation. Example of these parts are industrial-made metal foams or micro-lattice structures produced by SLM technology. This paper focuses on low-velocity dynamic loading prediction of BCC micro-lattice structure made of aluminum alloy AlSi10Mg by SLM technology (SLM 280HL). For this purpose dynamic FEM simulaton of the micro-lattice structure was developed, supplemented by model of BCC structure material obtained from mechanical testing. Real geometry of tested samples obtained from optical measurement (Atos Triple Scan III) was further implemented in the numerical model. Dynamic BCC structure load experiment was performed on a drop-weight tester. Behavior of structured material in drop-weight test was described by the course of deformation and reaction forces over time. Comparable results were obtained for flat loading of dynamic FEM simulation and experiment. Inclusion of production phenomena in simulation led to increased accuracy and compliance with experiment. Tool for testing the effect of geometry change on mechanical properties was created. To achieve more accurate results with puncture load, it is necessary to modify the material model with real material deformation at test sample failure.
Design of injection molding cooling insert for manufacturing by Selective Laser Melting
Tekeľ, Richard Martin ; Vrána, Radek (referee) ; Koutný, Daniel (advisor)
This bachelor thesis focus on design of a cooling insert so the current mold cycle time will be reduced and it will be possible to manufacture the insert by SLM. Proposed modification includes 1 cooling line with non-circular cross section and disrupt empiric cooling line design recommendations. A research into differences of conventional and additive manufacturing of injection moulding inserts was conducted as well as into theoretical principles needed for a design of cooling lines and preview of similar solutions for the given task. After simulation of current state and obtaining a value of current cycle time, 3 different designs of cooling line were chosen and simulated in order to pick the most suitable one. This cooling design was afterwards modified to get conformal shape and lower distance from critical spot. The last part of thesis interpret the results from simulation of the final cooling line design and estimation of safety against fatigue failure.

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