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Technology of manufacturing of carbon fibre composites by hot forming
Přikryl, Pavel ; Slaný, Martin (referee) ; Zouhar, Jan (advisor)
This master’s thesis deals with the composite materials and especially aims on the carbon and glass fiber composites. It points out different composition types and manufacturing methods which reflect in the different mechanical properties, final quality of the manufactured part and also in the manufacturing time. The practical part includes two particular manufacturing methods using prepregs, one cured in an autoclave and one by hot compression moulding.
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Additive in unsaturated polyester resin for pultrusion process
Vaněk, Martin ; Bábík, Adam (referee) ; Přikryl, Radek (advisor)
Theoretical part of bachelor’s thesis deals with composite materials based on fiberglass and unsaturated polyester resins. It focuses on Low profile aditives, which are added in matrix to lower polymerization shrinkage. The thesis studies the influence of additives on the changes of matrix behavior and mechanical composite properties. Nature of those changes was monitored by differential scanning calorimetry (DSC), scanning electronmicroscopy (SEM), touchscreen profilometry, tensile test and bending test. Influence of LPs on matrix polymerization shrinkage, roughness and geometry in fiberglass composites were evaluated. Matrix Polipol 3870 and aditive Norsolook A71074 were found to be the most suitable because the best result was observed.
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Robotic machining of composite materials
Rubišar, Václav ; Sedlák, Josef (referee) ; Zouhar, Jan (advisor)
This thesis deals with the robotic machining of composite materials. It is divided into two main parts - theoretical and practical part. The theoretical part is focused on detailed introduction of the term “an industrial robot” and a description of its controls, types of the robots, types of their propulsion and programming methods. Furthermore, there is a list of CAM softwares with its specification designed for both conventional machining and machining by using a robot. It also includes the introduction of composite materials and specification of their machining. The practical part deals with selection of appropriate type of bracket spindle by using a simulation software, suction design and economic evaluation of two types of machining in manufacture.
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Application of composite materials for sport optics
Kupčák, Radim ; Slaný, Martin (referee) ; Zouhar, Jan (advisor)
In Its first half this master's thesis describes composite materials with carbon fiber reinforced plastics being the main focus point. An overview of production technologies follows. The major objective of the second part of this master's thesis is to design and manufacture a simplified model of an optical device using prepregs.
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Testing of polymeric piezoresistive materials for use in pressure sensors
Janík, Jan ; Chladil, Ladislav (referee) ; Čech, Ondřej (advisor)
The aim of the bachelor’s thesis is to choose convenient piezoresistive and conductive materials for pressure sensors in the field of e-textiles. Thesis is divided into practical and theoretical part. Theoretical part deals with piezoeresistive effect itself and describes composite and piezoresistive materials. Practical part is focused on laboratory measuring resistance and capacitance of pressure materials and sensors in dependence on stress level. This part also includes practical reliability testings of conductive materials using accelerated aging testing methods.
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Machining of bio-composite materials
Obid, Daniel ; Slaný, Martin (referee) ; Zouhar, Jan (advisor)
This diploma thesis is focused on machining of composite materials mainly from natural fibers. The first part describes the production of composite materials and the methods used for their machining. The practical part of the work is devoted to the study of the influence of tool choice and cutting conditions on the cutting process and the quality of machined surfaces. The measured data are analysed using regression analysis.
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Mechanical Reinforcement of Bioglass®-Based Scaffolds
Bertolla, Luca ; Prof. Dr.-Ing. habil. Aldo R. Boccaccini (referee) ; Kotoul, Michal (referee) ; Pabst, Willi (referee) ; Dlouhý, Ivo (advisor)
Bioactive glasses exhibit unique characteristics as a material for bone tissue engineering. Unfortunately, their extensive application for the repair of load-bearing bone defects is still limited by low mechanical strength and fracture toughness. The main aim of this work was two-fold: the reinforcement of brittle Bioglass®-based porous scaffolds and the production of bulk Bioglass® samples exhibiting enhanced mechanical properties. For the first task, scaffolds were coated by composite coating constituted by polyvinyl alcohol (PVA) and microfibrillated cellulose (MFC). The addition of PVA/MFC coating led to a 10 fold increase of compressive strength and a 20 fold increase of tensile strength in comparison with non-coated scaffolds. SEM observations of broken struts surfaces proved the reinforcing and toughening mechanism of the composite coating which was ascribed to crack bridging and fracture of cellulose fibrils. The mechanical properties of the coating material were investigated by tensile testing of PVA/MFC stand–alone specimens. The stirring time of the PVA/MFC solution came out as a crucial parameter in order to achieve a more homogeneous dispersion of the fibres and consequently enhanced strength and stiffness. Numerical simulation of a PVA coated Bioglass® strut revealed the infiltration depth of the coating until the crack tip as the most effective criterion for the struts strengthening. Contact angle and linear viscosity measurements of PVA/MFC solutions showed that MFC causes a reduction in contact angle and a drastic increase in viscosity, indicating that a balance between these opposing effects must be achieved. Concerning the production of bulk samples, conventional furnace and spark plasma sintering technique was used. Spark plasma sintering performed without the assistance of mechanical pressure and at heating rates ranging from 100 to 300°C /min led to a material having density close to theoretical one and fracture toughness nearly 4 times higher in comparison with conventional sintering. Fractographic analysis revealed the crack deflection as the main toughening mechanisms acting in the bulk Bioglass®. Time–dependent crack healing process was also observed. The further investigation on the non-equilibrium phases crystallized is required. All obtained results are discussed in detail and general recommendations for scaffolds with enhanced mechanical resistance are served.
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Production technology of fiberglass parts
Nenov, Stanislav Stojanov ; Hodas, David (referee) ; Kandus, Bohumil (advisor)
Diploma thesis is focused on production technology of the glass fibre polyester part. It introduces characteristics of the composite materials and their dividing by the reinfocement geometry, reinforcement dimensions, reinfocement material and matrix materiál. In the final chapters thesis describes production technologies and proces of launching new part from 3D data to data and drawings of the mould including creation of the technological process.
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Precise bonding of composite materials
Tellinger, Adam ; Gregor, Lukáš (referee) ; Kupčák, Radim (advisor)
This bachelor's thesis deals with the issue of bonding composite materials. The first part of the bachelor's thesis is focused on research into the production of composite materials and gluing technologies. The content of the practical part is the design of test specimens and a preparation for their bonding with subsequent production. Furthermore, verification of compliance with the required accuracy of bonded joints when using different adhesives using 3D measurements.
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Use of 3D printing in the production of functional prototypes for automotive
Mikulášek, Marek ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This thesis deals with the 3D printing of composite materials. The constant development of this technology has enabled the application of this method for the production of prototypes, but also functional components. The theoretical part deals with the study of composite materials and the principle of production using additive technology. In the practical part, an analysis of the suitability of part processing using the 3D printing method is performed on a specific component and than applicated to the assembly hall located in ŠKODA AUTO a.s.
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