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Monitoring the durability of FRP composite materials
Janák, Petr ; Prokeš,, Jan (referee) ; Bodnárová, Lenka (advisor)
This diploma thesis deals with evaluation of the conditions for laboratory testing of composite profiles with fiber-reinforced polymer (FRP). Theoretical part describes the main material properties of FRP profiles and method of manufacturing by pultrusion. Experimental part evaluates imposition of the test samples in alkaline environment and their subsequent changes in physical properties. Next part contains evaluation of cuts FRP profiles by electron microscopy in combination with element analysis. The outcome of this work is the method of evaluation of accelerated durability FRP profiles.
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Dielectric absorption of varnish composites
Reňák, Ladislav ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
This work deals with issues of electro insulating varnishes and composite materiále within the frame of dielectric changes depending on a change of relative humidity where these varnishes are located. For this purpose had been created variety of a samples of electroinsulating varnish with different percentage of filling with mica. The general aim is acquire information about dielectric changes of examined electro insulating varnishes that are exposed to atmospheric influence.
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Study of electric properties of composite
Macháček, Miroslav ; Havlíček, Svatopluk (referee) ; Polsterová, Helena (advisor)
This work deals with issues of composite materials. The general aim is to observe how the amout of filling infuence dielectric spectrum which is measured on prepared samples. For this purpose had been created variety of a samples with different percentage of filling with mica. Measured values had been compared with theoretically values, determinated using mixture formulas.
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Short fiber reinforced composites in dental applications
Matysová, Dorota ; Vladimír, Pavelka (referee) ; Poláček, Petr (advisor)
This diploma thesis deals with short-fibre reinforced composites for dental applications. Particulate barium filler, short polyacrylonitryle fibres or short glass fibres were added to the dimethacrylate matrix to study their effect on the composite material properties. Methods used for this study were thermogravimetric analysis (TGA), differential compensation photocalorimetry (DPC), dynamic mechanical analysis (DMA), three point bending, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The matrix curing was defined by heat of polymerisation, degree of conversion and polymerisation rate. Composite materials were characterized by the glass transition temperature, storage moduli at 35 °C and 100 °C, elastic modulus, strength, the critical value of stress intensity factor and the critical value of energy release rate. Fracture surface investigation is also included in this thesis.
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Properties of pultruded composites based on epoxy matrix
Huljak, Pavel ; Bálková, Radka (referee) ; Přikryl, Radek (advisor)
The theoretical part of this bachelor thesis deals with research of composite materials, especially based on polymer epoxy and polyester resins, using as reinforcement a glass fiber bundles. The practical section includes the production of composite materials and their components along with the most important testing methods. The main goal of the experimental part is to characterize the optimal conditions pultrusion production of epoxy composite material. Another point is characterization of mechanical and chemical properties of the produced composite at a number of test methods. Finally the optimized epoxy composite materials are compared with composites based on polyester resins.
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Mechanical and structural characteristics of magnesium alloys reinforced with ceramic fibers
Halmazňa, Jiří ; Moravčík, Igor (referee) ; Zapletal, Josef (advisor)
This bachelor thesis deals the study of the mechanical properties of the alloy QE22 reinforced with SiC particles and Saffil fibers. This composite was produced by infiltration particles shape of the preform with molten matrix under high pressure. Test specimens prepared from the composite and the matrix were subjected to a tension strength test and compression test. The test results show pronounced asymmetry behavior in tension and compression of the matrix and composite. Adding the reinforcement into base material leads to significant increase of elastic modul, breaking strength and yield strength while reducing plastic properties. At the end of work was the behavior of the composite compared with the theoretical composite models.
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Replacing of metal sheets with laminates
Ulrich, Josef ; Němec, Karel (referee) ; Molliková, Eva (advisor)
The aim of the bachelor´s thesis is composite material, specifically fiberglass. In the first part of this thesis fiberglass is described, their composition, chosen production technology and possibility of use. Mechanical properties and its advantages of fibreglass are compared with metal sheets. Fibreglass is described on example of particular component.
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The composites materials based on the solid residues of fluidized combustion
Kalina, Martin ; Koplík, Jan (referee) ; Opravil, Tomáš (advisor)
This bachelor thesis deals with a study of possible preparation of composite materials based on the solid residues of fluidized bed combustion. It focuses mainly on the strength properties of prepared materials and the phase composition of incurred hydration products. A powder X-ray diffraction analysis was used to determine the phase composition of prepared stiffened samples. Based on analysis of raw materials (fluid ash), various ingredients and additives were added to the mixtures in order to modify the composition or rheological properties of the fresh mixtures. After 28 days of maturation, the phase composition of prepared samples and the development of compressive and tensile strength in bending were monitored.
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