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Modification of the filler in cement-bonded boards with alternative filamentous fillers
Dywor, Michal ; Vacula, Miroslav (referee) ; Bydžovský, Jiří (advisor)
The cement boards are commonly used as a filler fir or spruce chips-profit wood. The increasing demands for construction materials forcing technology to develop new types of composite materials using an alternative source of fillers. In this work in the context of theoretical knowledge about the specified fibers in composite systems are discussed properties of cement binder and filler for cement – bonded particleboards and alternative materials. The practical part describes the test methods designed recipes and then made boards of which were carved specimens intended for testing the properties of boards with alternative fillers.
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Controlled heating of Composite Material
Fajkus, Martin ; Macháň, Ladislav (referee) ; Šteffan, Pavel (advisor)
The supposed thesis considers problem of heating of composite material for outdoor application. Basement of thesis is analysis of submitted sample of composite material. Measured values of composite material were compared and evaluated and than acceptable samples were choosen for next application. Part of thesis is creation of measuring software for analysis of sample. Other part of thesis is realization of equipment of control unit for heating of composite material. Control unit makes it possible to regulate heating and to set up parameters from computer.
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Manufacturing Process and Applications of Composite Materials for buses parts
Rusek, Jan ; Julišová, Martina (referee) ; Němec, Karel (advisor)
The aim of the bachelor’s thesis is the evaluation and demonstration of the usability of composite materials in the bus industry. The first chapter provides an overview of selected types of composite materials, basic classification, description of their parts and demonstrations of methods of production. The second part of the bachelor’s thesis is focused on the evaluation of the advantages and disadvantages of using composite materials. The last part is focused on the producion of the sample from fiberglass.
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Composite materials with silica matrix in the environment of high temperatures
Lisztwanová, Ewa ; Luňáček,, Martin (referee) ; Bydžovský, Jiří (advisor)
This thesis deals with the study and design of composite materials based on silica matrix suitable for extreme conditions, eg. for the repair of concrete structures with anticipated increased risk of fire. The theoretical part summarizes basic knowledge concerning the fire resistance of structures and the behavior of the composite system during extreme conditions. Theoretically oriented section also contains information on alkali-activated materials and their use in high temperature environments. Based on the evaluation of the theoretical part of the experiment were designed and tested different types of composite materials with increased content of raw materials from alternative sources. Laboratory research has been based on testing of basic physico-mechanical parameters including phase composition and microstructure of the proposed formulations before and after thermal exposure of 1200 ° C. Also considered was the effect of different cooling conditions.
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Restoration of masonry building
Hubený, Radim ; Pulec, Vladimír (referee) ; Perla, Jan (advisor)
The final thesis is focused on restoration masonry building. Concretely assessment of resistance joist's floors, design alternative's strengthening and impact of surcharge on pronounces constructions. The choice one of alternatives strengthening, design and check of floor structure over the second floor.
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Preparation of MDF composites of increased moisture resistance
Žůrová, Marcela ; Šiler, Pavel (referee) ; Šoukal, František (advisor)
The subject of the thesis is to improve the moisture resistance of MDF (macro-defect-free) composites prepared on the basis of aluminous cement and polyvinyl alcohol. These materials are characterized by the absence of defects in the structure and high mechanical performance. These features make MDF composites a promising type of material that could be used in the future for construction purposes. The basic deficiency of MDF composites is insufficient resistance to water or moisture, accompanied by a significant decrease in strength. Therefore, this work deals with increasing of moisture resistance using organotitanate agent and modification of the polymer. Two types of polyvinyl alcohols differing in hydrolysis degree and degree of the polymerization has been modified. Based on the results of the measurement the effect of storage conditions on the properties and structure of prepared MDF composites was observed. The characterization of MDF composites were realized by measurement of flexural strength in bending, scanning electron microscopy with EDS analysis, TG-DTA-EGA, water absorption and consequently the porosity of all prepared MDF composites.
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Wing structure
Kaňák, Ondřej ; Weis, Martin (referee) ; Jebáček, Ivo (advisor)
This bachelor’s thesis deal with the wing structure of small aeroplanes. Step by step we are discovering different kinds of constructions and their usage in aerospace industry. Characteristic signs (shape, geometric,load), advantages and disadvantages construction types are shown in this work.
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A comparative study of ultimate load and stiffness of metal-to-composite joints
Tchír, Michal ; Šebek, František (referee) ; Vrbka, Jan (advisor)
V současnosti jedna z metod spojování zejména tlustých a vysoce zatížených kompozitních komponent je šroubový spoj, který je možné rozebrat pro případ opravy na rozdíl od lepeného spoje. Kompozitní konstrukce se tradičně dimenzují tak, aby během provozu nedošlo k porušení první vrstvy laminátu, nicméně důležité je taky poznat chování laminátu po porušení první vrstvy. Pro strukturální analýzu nejenom spojů, ale také dalších komponent se používá metoda konečných prvků a protože moderní nelineání řešiče jsou schopné modelovat chování laminátu po porušení první vrstvy, tato schopnost jednoho z nich byla využita v této práci při zkoumaní chování sklolaminátu spojeného s hliníkovou částí šrouby. Konečno-prvkové modely dvou spojů kovové a kompozitní části konstrukce schopné popsat progresivní porušování laminátu byly postaveny s využitím tří různých poruchových kritérií – kritéria maximálního napětí, kritéria Hill a kritéria Tsai-Wu. Problém byl řešen s využitím řešiče Nastran. Křivky síla-posuv, tuhost-posuv a hodnoty zatížení při hraničním posuvu byly porov-nány s výsledky experimentů. Jelikož faktor zbytkové tuhosti ovlivňuje výsledky ana-lýzy progresivního porušování, byly provedeny citlivostní studie zkoumajíci vliv faktoru na přesnost a stabilitu výpočtu. Shoda výpočtu s experimentem v případe prvního šroubového spoje je méně uspokojivá, nicméně shoda v případě druhého spoje, který má zesilující tenkou ocelovou destičku na spodní straně, je podstatně lepší. Vý-borná shoda je zejména při použití interaktivních kritérií Hill a Tsai-Wu.
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The use of Electrical Properties of Composites with Modified Cement Matrix
Macháň, Ladislav ; Husák, Miroslav (referee) ; Sýkora, Jiří (referee) ; Šteffan, Pavel (advisor)
The dissertation thesis is focused on practical use of composite material with modified cement matrix. Especially the area of electrical behavior of composite materials in use has been examined, for strain sensing material. The experimental part solves the problematics of corrosion of carbon and metallic materials in alkaline environment of the cement matrix. The physical design of the sensor and its fabrication using functional composite cement material have been described here. The thesis has also discussed defining the influence of temperature change and humidity change on the change of electrical parameters of integrated sensors. An important part of the thesis is the area of evaluating a series of measurements of electrical parameters under dynamic loading. The thesis analyzes designed measurement method in detail, being suitable to determine electrical properties of cement composite materials including the construction of a monitoring system that enables practical application of sensors in complex structures.
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Study of inorganic matrix composites for FRP
Svora, Petr ; Rovnaník, Pavel (referee) ; Puliš,, Pavel (referee) ; Šubrt,, Jan (referee) ; Bodnárová, Lenka (advisor)
During a whole period of time which fibre-reinforced polymers have been used in the building industry, in dominating bonding agent has been the organic resins. There is no doubt about their advantages, but at the same time, they have two weaknesses: they are not fire resistant and they have no resistance to high temperature. Those are the reasons why the research on alternative materials which could replace organic matrix has been undertaken. The goal of the work is to maintain mechanical properties of fibre-reinforced polymer with organic matrix. Of course, an emphasis is placed to fulfilling ecological standards which are required from ecological material. An aluminosilicate inorganic matrix can meet them all. It is non-flammable, does not produce any toxic matter in contact with fire and the energy consumption during production process is lower than in case of the organic matrix. This work includes study and analysis of selected raw materials as well as their influence and impact on final reaction products which are created in inorganic matrix. A part of this work is also a design of the inorganic matrix recipe.
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