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Comparison of tensile properties of polymeric samples produced by extrusion based 3D printing
Krajcar, Ivo ; Vespalec, Arnošt (referee) ; Škaroupka, David (advisor)
The subject of this work is a summary of the contemporary knowledge about 3D printing and mechanical properties of a prototype manufactured this way. Main goal is to compare the frequently used FDM method with the innovative APF method of 3D printing from the Arburg company. ASA and CPE materials were chosen for researching this method. On these materials, tensile strength was measured. Aditionally, for comparison between the two methods, referential samples manufactured by injection moulding were made. A percentual difference in strength of each sample was compared against these. 60 samples in total were made for this comparison. After evaluation of the results, it was found that in the tensile strength the samples made by the APF method are approximately 30 % less strong than the referential sample. The samples made by the FDM method are approximately of the same strength as the referential sample.
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Controlled life-time polypropylene
Demková, Eva ; Petruš, Josef (referee) ; Tocháček, Jiří (advisor)
The master´s thesis is focused on the characterization of degradation process of polypropylene and polypropylene with statistic copolymer into which manganese (II) stearate and cobalt (II) stearates were added at 0.05, 0.10 and 0.20 wt.% loadings. The aim of the thesis was to prepare the controlled life-time polypropylene. The degradation was studied at varying temperatures and prodegradant loadings. The prodegradants were synthetized and characterized using the FTIR and DSC techniques. Thermooxidation of the tested samples induced the changes in crystallinity, melting points and melt-flow indexes. Tensile strength and other mechanical properties were determined by means of the tensile test. The carbonyl index was determined using FTIR, the thermooxidation stability test was used to determine the activation energies of reactions. The changes in morphology of degraded samples were observed by SEM analysis.
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Influence of input material on technology and production of deep drawn product
Černá, Monika ; Peterková, Eva (referee) ; Šulák, Ivo (advisor)
This bachelor thesis was elaborated in cooperation with company ITW Pronovia, s.r.o within the scope of the bachelor degree and presents an assessment of the effect of material properties and manufacturing technology of a deep-drawn product. In this work the mechanical and technological tests were carried out on the supplied material HT179. This material is further processed into a cartridge for an airbag deployment. During production many defects occurred, especially after cutting out the holes of deep-drawn product. The company established these defects as material property. Therefore it is necessary to evaluate the characteristics of different material sets.
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Mechanical properties of 3D printed PLA plastic parts
Novosád, Ivan ; Dočkal, Kryštof (referee) ; Paloušek, David (advisor)
3D printing is being widely used by public and also in industry. The main advantage of 3D printing is rapid making prototypes. That is the reason why it is needed to know what the mechanical properties of the material that is being used are. This thesis is about making research of knowledge about 3D printing and mechanical properties of printed parts. Main task was comparing materials used in 3D printers and find out which producer makes materials with the best tensile strength. 5 producers were selected to be compared in this test. From each producer was bought PLA filament in natural colour, this material was then used to print testing specimens. All specimens were tested on maximum tensile strength and Young's elastic modulus and then was calculated the confidence interval for each producer.
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Influence of Homogenizing on Mechanical Properties of AZ91 Alloy
Provazníková, Andrea ; Liškutín, Petr (referee) ; Věchet, Stanislav (advisor)
This bachelor thesis includes photos and graphic representations of the influence of heat treatment on the mechanical properties of magnesium alloy AZ91. The structures of the alloy are recorded on the light microscopy pictures as well as photographs taken using a scanning microscope of fracture areas in the material. Results of a Tensile Test determining the strength and plastic properties and measuring of hardness and microhardness of the material are also included.
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Possibilities of the description of stress-strain curves for computational simulations
Košťál, Josef ; Halabuk, Dávid (referee) ; Šebek, František (advisor)
Tato bakalářská práce se zabývala problematikou určování křivky zpevnění (taktéž „flow curve“) z experimentálně změřených výstupů tahové zkoušky a regresí této zjištěné křivky nelineárními vztahy. Byl prezentován teoretický základ zkoušky tahem a jejího výstupu a také byly popsány rozdíly mezi smluvním a skutečným napětím a přetvořením. Dále byla zmíněna analytická korekční metoda (Mirone-La Rosa) pro odhadnutí trendu křivky zpevnění. Tato metoda využívá standardních výstupů tahové zkoušky. Dále byly vypsány elasto-plastické po částech spojité materiálové modely, a navíc byly vybrány a detailněji rozebrány 4 nelineární vztahy pro popis křivky – Hollomon, Ludwik, Swift a Voce. Následně byla použita metoda konečných prvků pro určení a zkalibrování křivky zpevnění oceli 18CrNiMo7-6, změřené tahovou zkouškou. Pouze standardní výstup tahové zkoušky byl potřeba pro kalibraci. Křivka zpevnění byla zkalibrována iterační výpočtovou metodou na základě srovnání reakční síly ze simulace se silou z experimentu. Nakonec bylo vytvořeno uživatelské prostředí pro nalezení nejlepší regrese ze čtyř vybraných nelineárních vztahů.
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Testing of parts produced by Bound Metal Deposition technology
Hradil, Antonín ; Vaverka, Ondřej (referee) ; Koutecký, Tomáš (advisor)
Bachelor thesis on the topic Testing of parts produced by Bound Metal Deposition technology. Aim of the work is to obtain mechanical properties of products made by Studio System. We have achieved this by performing tensile test and optical metallography. The results of this thesis are mechanical properties of the tensile test. Re, Rm, E, etc. Another results are microscopic images of microstructure of material. Thanks to this work, we are getting closer to the technology Bound Metal Deposition. We approximate scientifically its mechanical properties and the microstructure of the product surface.
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Testing of commercial rubber sealing components exposed to different ambient conditions
Jančaříková, Marie ; Poláček, Petr (referee) ; Bálková, Radka (advisor)
Diploma thesis studies the effect of temperature (75 and 105 °C) and the effect of 3 kinds of liquids (silicone and hydraulic oil and coolant) at room temperature and at 105 °C on change of the structure of 3 species butadiene-acrylonitrile (NBR) seals (o-ring and two types of bolts). The seals are inspected by the thermogravimetric analysis, differential scanning calorimetry and infrared spectroscopy, the influence of 105 °C on the o-rings is also evaluated in terms of changes in tensile properties. The greatest changes in the composition and structure are observed on o-rings particularly due to temperature of 105 °C, there was a significant reduction in dilatability and an increase in stiffness and glass transition temperature. The root cause is the surface and centre additive decomposition and oxidation. The bolts have suffered from decomposition of the protective surface layer and the additives in the centre, structural change was minor. Exposure to 75 °C has resulted in a gradual loss of low molecular weight substances. Liquids at room temperature didn‘t affect the structure of the seals, at 105 °C it caused a loss of weight due to decomposition of the protective surface layer and release of additives and the products of their decomposition. Results showed that the common use of the NBR seals at 105 °C is unsuitable, at 75 °C it leads to gradual changes, loss in mechanical and sealing properties.
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Physical ageing of polypropylene
Weiss, Jiří ; Kučera, Jaroslav (referee) ; Tocháček, Jiří (advisor)
Physical aging of commercially produced polypropylene homopolymers Mosten was studied. The work is focused on monitoring the changes in physical properties of polymer in the time period 90 days from the date of preparation of the test specimen. The aging of polymers was realized at storage temperatures of 23 and 80 °C. The changes in crystallinity, yield strength, modulus, elongation and impact strength using DSC method, tensile tests and impact tests according to Charpy were monitored. Molecular weight distribution was determined by means of GPC at each polymer. Relationships between the changes in physical properties and polymer molecular weight were sought.
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