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Plasmochemical treatment of natural fibres
Demková, Eva ; Mazánková, Věra (referee) ; Přikryl, Radek (advisor)
This bachelor thesis is focused on plasmochemical surface treatment of natural flax fibres using dielectric barrier discharge and silane coupling agent. Treated fibres were used as reinforcement of composite material with an epoxy matrix. Composite materials were prepared manually, by placing saturated fibres into silicone mold. Mechanical properties of composite materials were determined by bending test, tensile test and dynamic-mechanical analysis (DMA). The presence of a silane coupling agent on the surface of the fibre was detected by EDS analysis. SEM method was also used to determine the effect of plasma on the surface of fibres.
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Optimalisation of coposite materials for civil engineering
Kazda, Tomáš ; Chladil, Ladislav (referee) ; Novák, Vítězslav (advisor)
This work is focused on optimalisation of coposite materials for civil engineering. In the theoretical part of the project is introduction of the composite materials and materials which are used for their production. There are also concerned their properties and possible application areas. In conclusion of theoretical part this project is a summary of the possible use of composite materials. The practical part compares the characteristics of the different types of composites made in terms of conductivity and the rate of corrosion.
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Experimental comparison of shear properties of FRP measured by ASTM methods
Ponížil, Tomáš ; Mališ, Michal (referee) ; Urík, Tomáš (advisor)
Přesné určení konstitutivních smykových závislostí napětí na deformacích je základem pro pochopení chování anizotropního kompozitního materiálu. Bylo vyvinuto mnoho zkoušek smykových vlastností kompozitních materiálu. Jelikož vyvolání čisté smykové napjatosti je složité, tento stav je vyvolán pouze některými z nich. V této práci je ověřeno použití systému Aramis k vyhodnocení průběhu smykového přetvoření a následnému výpočtu konstitutivních smykových vlastností při provedení jednoduché zkoušky ohybem krátkého nosníku. Tyto výsledky jsou dále porovnány se zkouškou podle Nicolae Iosipesca.
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Filling materials for vertical and horizontal constructions using renewable raw materials
Gregor, Petr ; Vacula, Miroslav (referee) ; Bydžovský, Jiří (advisor)
This thesis deals with industrial hemp and its use in vertical and horizontal structures. The work is mainly focused on the fillers of industrial hemp and inorganic binder. In the practical part of the feasibility study for future use of industrial hemp in the construction industry as a filling materiál in vertical and horizontal structures. This area has been targeted by all test samples. They are presented here and evaluated and compared the results of tests on unconfined compressive strength, compressive strength, depending on the deformation density of fresh and hardened mixture and the termal conductivity of different types of inorganic binders and fillers such as hemp.
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Boards with alkali activated binder filled with wood chips
Gajdušková, Patricie ; Vacula, Miroslav (referee) ; Bydžovský, Jiří (advisor)
For the production of cement chipboards, cement is used as a binder which is an ecological burden for our planet. This diploma thesis deals with research into the possibility of replacing it with other alternative materials, especially those that are created as a by-product of other production. The focus is primarily on slag, heating plant slag or brick dust. The theoretical part deals with the previous studies and theoretical knowledge of alkaline-activated matrices which are supplemented with an organic binder such as wood chips which are used to reinforce the boards. The practical part deals with the above-mentioned alternative materials which are tested for the design of recipes for modified boards made of alkali-activated binder reinforced with chips. These modified recipes are subsequently subjected to physical-mechanical tests such as bending strength, modulus of elasticity and other monitored parameters of the boards. Selected board variants were analysed in terms of mineralogical composition and microstructure.
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Study of bioceramic composite based on hydroxyapatite and bioglass
Virágová, Eliška ; Hadraba, Hynek (referee) ; Drdlík, Daniel (advisor)
This bachelor thesis is focused on the bioceramic composite materials based on hydroxyapatite (HAp) and bioglass (BG). The wet shaping method, i.e. electrophoretic deposition (EPD), was chosen for the preparation of these materials. The methodology of preparation and its influence on kinetics, relative density and pore distribution in the prepared composites was evaluated. The sintering process of the prepared composites was studied using high temperature dilatometry with subsequent evaluation of their microstructural and mechanical features. It was found that EPD is an applicable method for successful preparation of the particle composites. The microstructural quality of particle composites was affected mainly by the electrical conductivity of the suspension. It was found during the study of EPD kinetics that the highest deposition rate was achieved in the suspension with the lowest electrical conductivity. Increasing amount of BG in HAp caused increase of the relative density and pore diameter whereas the volume of pores decreased. High temperature dilatometry showed a decrease of relative shrinkage, which was evident with increasing HAp amount in the structure. Observation of the microstructure revealed a crystalline structure of BG and an open porosity of HAp, which is desired for biocompatible materials. The phase composition of the materials was determined by X-ray diffraction analysis. In case of the mechanical properties it was found an increase of the hardness and Young’s modulus of elasticity with the increasing amount of BG in bioceramic composites. Based on the obtained results the suitable process and material composition for the planned preparation of the functionally graded material were identified.
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Tail units design of VUT 100 aircraft made out composite
Berka, Martin ; Cejpek, Jakub (referee) ; Mališ, Michal (advisor)
This Master´s thesis describes the design of composite horizontal tail of VUT 100 aircraft. Load calculation and selection of the critical load cases is performed. Internal structure of stabilizer and right elevator is designed. Construction materials are chosen and the structure of the composite materials is proposed. FEM models of stabilizer and the right elevator are created in MSC Patran system and consequently the strength test of the models for the selected load cases is executed using MSC Nastran software and COMPOST.
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Geopolymers Incorporating Wastes and Composites Processing
Taveri, Gianmarco ; Perná,, Ivana (referee) ; Pouchlý, Václav (referee) ; Dlouhý, Ivo (advisor)
Buildings construction and realization of public infrastructures have always been a primary need in the human society, developing low cost and user-friendly materials which also encounter safety and durability requirements. Portland cement is the most used material in construction industry from the industrial revolution up to date, but the raising concerns related to the climate change are pushing the governments worldwide to replace it with more eco-friendly and greener materials. Geopolymers are considered to be best alternatives to Portland cement in construction industry, but issues related to cost and mechanical properties are still hindering the commercialization of this material. Geopolymer incorporating wastes is one of the solutions. Fly ash, a thermal power plant by-product, and borosilicate glass, a recycled glass from pharmaceutical vials, are suitable candidates in geopolymers activation. NMR and FTIR spectroscopies demonstrated that borates from borosilicate glass are active compounds in geopolymerization, substituting the alumina is its role, composing a B-Al-Si network never observed before. Various fly ash and borosilicate glass weight contents were studied in terms of mechanical properties (compression test, 3-point bending test). It was found that fly ash 55 wt.% and borosilicate 45 wt.% composition activated in 13 M NaOH solution holds the best compressive and flexural strength (45 and 4 MPa respectively), 25% stronger than similar counterparts found in literature. Cellulose fibres in different weight contents were dispersed into the geopolymeric paste to produce geopolymer composites, with the aim to render the material more suitable for structural applications. 3-point bending test showed an improvement of the flexural strength of about 165% (12 MPa), while the chevron notch method displayed a fracture toughness of 0.7 MPam1/2, in line with the results of geopolymer composites found in literature. In this thesis work, fly ash was also successfully densified in 3 M NaOH solution and distilled water through a new method based on hydraulic pressure, called hydro-pressure sintering. This innovative technology involves a drastic reduction of NaOH utilization in geopolymerization, rendering the material more eco-friendly. XRD spectroscopy conducted on produced samples revealed a higher formation of crystals, most likely induced by the application of hydraulic pressure (450 MPa).
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Manufacturing of thermoplastic composites
Makariv, Štefan ; Gregor, Lukáš (referee) ; Zouhar, Jan (advisor)
This thesis investigates the mechanical properties and application possibilities for use in the manufacture of functional parts of Endumax Shield XF33 and Twaron CT 747 TH110 thermoplastic composite materials intended for ballistic applications. To investigate the properties of the materials, it was necessary to design and fabricate a prototype pressing jig with a heating and cooling system for the production of composite material samples by the hot-pressing method. The steps during the design of the pressing jig and the subsequent production of the samples were described. The specimens were subjected to mechanical tensile and flexural tests. The results of the mechanical tests were compared with those of the autoclave produced Twaron CT 747 ER68 reactoplastic composite material and with the results of investigations of materials with similar compositions. The evaluation of the properties showed that the investigated thermoplastic composite materials do not have the properties for use in the manufacture of functional parts. The process conditions may have influenced the properties. Further technical work was recommended to investigate the process conditions in detail.
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Bonding of composite materials in precise applications
Hartmann, Kurt ; Gregor, Lukáš (referee) ; Kupčák, Radim (advisor)
A study on composite materials and adhesive technology was conducted as part of the research. The main objective of the work was to evaluate the suitability of selected adhesives for precision applications. The practical part focused on this objective and included the design and development of a special bonding preparation, enabling the creation of samples for subsequent strength testing.
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