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Composites Application in Automotive Industry
Bačovský, Marek ; Dundálek, Radim (referee) ; Ramík, Pavel (advisor)
This bachelor´s thesis deals with the use of composites in the automotive industry. The first part of the thesis processes overview of the basic properties of composites, their structure, characteristics, advantages and disadvantages. The second part focuses on their application in series manufacture and in racing cars, incl. Formula Student. The final section provides a view into the future and the overall evaluation of composite materials.
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Optimisation of cement-bonded particleboard matrix composition by using alternative raw material sources
Roháček, Lukáš ; Vacula, Miroslav (referee) ; Bydžovský, Jiří (advisor)
The diploma thesis deals with possibility of utilization raw materials from alternative sources for production of cement-bonded particleboards. In theoretical part the possibilities of modifying composition of cement-bonded slabs with emphasis on their matrix are discussed in detail. On basis of the findings and their evaluation, waste from the formatting of cement-bonded particleboards, micronized limestone, heat sink and high temperature fly ash were selected to the composition modification. The mentioned raw materials were analyzed and subsequently tested as substitutes for the matrix of cement-bonded particleboards in the experimental part. The properties of the proposed materials were tested even in the longer term, including the microstructure.
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Application of thermoplastic composite materials on aircraft structures
Vráblíková, Lucie ; Symonov, Volodymyr (referee) ; Klement, Josef (advisor)
This bachelor thesis deals with thermoplastic composite materials in aircraft industry. The aims of the thesis are divided into three parts. The first part contains an overview of the basic properties of fibre-reinforced thermoplastics, their structure and characteristics. In the second part, there are introduced different technologies of manufacturing thermoplastics. The last part deals with applications of thermoplastic composite materials in aircraft industry.
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Design of the Timber-Concrete Composite Ceiling Structure
Válek, Jakub ; Horák, David (referee) ; Švaříčková, Ivana (advisor)
The reconstruction of existing houses is currently a frequent issue. This work deals with the possibilities of reinforcing wooden ceilings with the focus on ceiling reinforcement using an over concrete slab. This suggested ceiling reconstruction work is desirable from the point of view of the rigidity of the object in the horizontal direction. The work includes the proposition for the composite, according to various norms and their comparison regarding the economic side of the design. The work further provides a description of the experiment, its preliminary results and its comparison with the theoretical calculation.
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Hybrid biopolymer composites for 3D printing applications
Menčík, Přemysl ; Bakoš, Dušan (referee) ; Dzik, Petr (referee) ; Jančář, Josef (advisor)
This dissertation work deals with the thermic and the mechanical behavior of plasticized bio-plastics and bio-composites for the 3D printing applications. The influence of plasticizer chemical structure on thermic and mechanical properties of plasticized polymeric blends from the poly-3-hydroxybutyrate and the poly lactic acid was investigated. Used plasticizers are based on derivative of citric acid. The influence of plasticizers on polymeric matrix and their compatibility was estimated by gear torque rate of melt mixer, respectively rate of plasticizer migration from the material during higher temperature. The plasticizer structure influence on the glass transition temperature and on the kinetics of crystallization of plasticized material was investigated by modulated differential scanning calorimetry. The behavior of material during 3D printing was also observed. Mechanical properties of printed samples, especially their elongation at break, were determined by tensile tests. The largest softening effect was observed using tributylcitrate plasticizer, where the glass temperature decreased by 35 °C and elongation at break increased by 150% compared to non-plasticized reference material. This plasticized polymeric blend showed also sufficient 3D printing properties and was used as the matrix for composites in the next part of this work. Composites were filled by kaolin, limestone, halloysit, fumed silica, talc, magnesium hydroxide and chopped flax fibers. Particle distribution in composites in dependence of used surface treatment of filler was observed by scanning electron microscopy. The influence of composite filler on rheological properties, crystallization kinetics and thermal stability of composites, was observed by viscometry and differential scanning calorimetry. Their mechanical properties and heat deflection temperature were observed on samples prepared by 3D print. Kaolin in composite material showed homogeneous particle distribution and insignificant nucleation effect and influence on thermic stability. Composite filled by kaolin also showed 18% smaller warping during 3D printing compared to non-filled reference. Consequently kaolin was evaluated as suitable inorganic filler for bioplastic composite intended for 3D print and this composite was used in the following part of this thesis. Method of mathematical prediction of Young's modulus was described for composite samples prepared by 3D print. Composites filled by one type of filler – kaolin, or limestone, resp. by combination of both fillers were investigated on the basis of the micromechanic Halpin-Tsai model modified by the semiempiric multiparametric Cerny's equation. Additive and combinational method of Young's modulus evaluation is used for composites with hybrid filling. Deflection of measured and theoretical Young's modulus value of composite filled with kaolin was decreased by established correction from 21% to 1% and for composites filled with limestone from 13% to 9%. In this manner it is possible to predict the Young's modulus of the samples prepared by 3D print.
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Targeted Preparation of Composite Based on PP with Inorganic Micro-, or Nanofiller with Different Adhesive Interlayer
Dombková, Julie ; Krčma, František (referee) ; Nezbedová, Eva (advisor)
The diploma thesis studies composite of PP and filler particle. As a particle filler was used commercially available CaCO3 (SOCAL 31). The submitted thesis had a goal to find new approaches and technologies of filler surface treatment in order to improve properties of composite materials. The plasma discharge behind static pressure was used for the surface treatment of the fillers. These fillers were afterwards analyzed by using of sedimentation analysis, turbidimetry, infra-red spectroscopy (FT-IR), X-ray diffraction analysis (XRD), scan electron microscopy (SEM), transmission electron microscopy and particle size distribution by laser diffraction. The composites with various volume parts of the fillers were prepared in PIB and studied by short-time tests. Furthermore, the influence of an adhesive layer on fracture mechanical properties of prepared composite was study. Regarding to experimental demand, there was not possible to realize long-term mechanical properties.
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Effects of Defects on Composite Structures Load Carrying Capacity: Delaminations at a Bi-Material Interface
Matěják, Vladimír ; Kotoul, Michal (referee) ; Růžička, Milan (referee) ; Juračka, Jaroslav (advisor)
Kompozitní materiály se projevují komplexním způsobem porušování, které může být dále ovlivněno přítomností různých poruch plynoucích z výrobních processů nebo se vyskytujících v průběhu života součásti. Důkladné porozmění procesů porušování a jejich okolností je nezbytné pro navrhování kompozitních konstrukcí, jenž budou bezpečnější, trvanlivější a ekonomičtější. V první části disertační práce jsou popsány způsoby porušování kompozitů a uvedeny současné matematické metody pro analýzu a výpočet únosnosti. Dále jsou zde vyjmenovány hlavní druhy vad a stručně diskutován jejich vliv na vlastnosti kompozitních materiálů. Zvláštní důraz je kladen na delaminace, společně se základními principy lomové mechaniky a jejich uplatnění při výpočtech a zkoušení kompozitů. Druhá část je zaměřena na delaminace na rozhranní dvou různých materialů. Lomová houževnatost byla experimantálně měřena ve třech typech zatížení za účelem stanovení poruchového kritéria založeného na podílu módu I a módu II. Během tohoto experimentu byla vyvinuta nová metoda měření délky trhliny pomocí digitáního zpracování obrazu a rovněž byla navržena nová definice počátku šíření trhliny. Analytické vztahy pro výpočet míry uvolnění deformační energie z naměřených dat byly rozšířeny o vliv rozdílných elastické parametrů materiálů na rozhranní. Podrobnější prozkoumání analytických vztahů a výpočet metodou konečných prvků odhalil, že podíl módu I a módu II je závislý na vzdálenosti od čela trhliny a poruchové kritérium založené na podílu smíšenosti tak nemůže být použito.
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Glass-ceramic composite biomaterials
Žaludek, Jakub ; Hadraba, Hynek (referee) ; Drdlík, Daniel (advisor)
The bachelor thesis is focused on the preparation of bioglass 45S5 and composites containing bioglass 45S5 and alumina or zirconia fibres in amount of 1, 3 and 5 wt% by slip-casting method from aqueous and 2-propanolic suspensions. The materials prepared were characterised in term their porosity, relative density, high temperature dilatometry, X-ray diffraction analysis, microstructure and hardness. The slip-casting method produced porous samples which is promising result for a possible biomedical application. The high temperature dilatometry identified three stages of the sintering process and a shrinkage of ~40% of the bioglass-based materials was measured. The crystalline phase of Na2Ca2Si3O9 was created at the sintering temperature of 1050°C but the dissolution of Al2O3 or ZrO2 fibres into the bioglass matrix was not confirmed using the X-ray diffraction analysis. It was found that the hardness of the samples decreased with the amount of the fibres in the materials which was caused by their increasing porosity and large clusters of fibres.
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