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Preparation and optimization of biocomposite material for pultrusion processing
Sousedík, Jan ; Figalla, Silvestr (referee) ; Menčík, Přemysl (advisor)
This thesis focused on the synthesis and subsequent use of polyester resin from renewable natural resources as a matrix for a biocomposite with flax fibre reinforcement. The synthesized bio-based resin was characterized by mass spectrometry (MS) and Fourier-transform infrared spectroscopy (FTIR). The pultrusion was method chosen for the preparation of the composite materials. The optimalisation of the individual components of the composite was carried out as part of the thesis. Two types of composite material were prepared, a composite with fibres surface modified by acetylation and a reference composite with unmodified fibres. The resulting composites were subjected to mechanical properties tests, namely three-point flexural test, tensile test, short beam shear test (SBS), Charpy impact test and dynamic mechanical analysis (DMA). The thermal properties were investigated by differential scanning calorimetry (DSC), heat distortion temperature test (HDT) and thermogravimetric analysis (TGA). In addition, the reinforcement adhesion was monitored by scanning electron microscopy (SEM). Determination of the water absorption of the composites was also carried out. Based on the results of the analyses, a positive effect of the surface treatment of fibres by acetylation on the mechanical properties of the composites was demonstrated.
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Kompozitní materiál vyztužený skelnými vlákny s různou orientací
Brychta, Ondřej
The aim of this diploma thesis is an experimental comparison of mechanical proper-ties of composite materials reinforced with differently oriented glass fibers. These were samples of polyurethane resin with a needled mat, which is used in the floor of buses as a supporting element of floors. The theoretical part is focused on the composition, composition of fibers and distri-bution of individual types of composite materials and on determining the production method that can be used in the production of composite materials in various areas of industry. At the same time, a comprehensive methodology for recording failure of composite material during tensile loading was proposed in the experimental part. During loading, samples were monitored by the optical digital image correlation (DIC) method to identify deformations on the test samples. This method has become a suitable tool for evaluation and characterization of the deposition of individual fabrics in tested samples. Thanks to this me-thod, individual failures occurring during tensile loading were detected. These were divided into certain typical phases of composite material failure. The samples for the experimental part are samples of polyurethane resin reinforced with a needled mat. The reinforcement structure is composed of a total of 6 layers. It is a two-layer material composed of woven roving and chopped mat. On the back of the U-profile is reinforced with glass-roving.
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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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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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Application of functional fillers in composites: Effects of fillers content on the mechanical properties
Krhut, Jiří ; Petruš, Josef (referee) ; Poláček, Petr (advisor)
This work deals with the application of selected types of fillers and monitoring their addition to the specific properties of the resulting composite material. The theoretical part of this work includes a general description of composite materials, and selected types of matrices, followed by a brief description of the characteristics of particulate composites and the effect of fillers on selected material properties. In the experimental part, samples of polyester resin were prepared to contain the given content of filler based on aluminium hydroxide (Al(OH)3), expanded glass, hollow glass microspheres, and fillers based on nitrogen and phosphorus compounds. Subsequently, the influence of the used fillers on the rheological properties, flammability of the material, on mechanical and thermomechanical properties was monitored. Flame test methods, bending test methods and dynamic mechanical analysis (DMA) were used to evaluate the samples. Finally, the measurement was supplemented by an analysis of fracture surfaces using a scanning electron microscope (SEM). The addition of additives improved the fire resistance of the prepared materials. The mechanical and thermomechanical properties of the prepared materials differed significantly depending on the applied fillers and their content.
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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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Structural design and stress analysis of ski landing gear for airplane with short take-off and landing
Hostinský, Vladimír ; Vaněk, František (referee) ; Katrňák, Tomáš (advisor)
The aim of this thesis is a design of a ski landing gear for the STOL Cruiser airplane and strength analysis of its parts with consideration of UL-2 and CS-LSA regulation requirements. First part follows the design process from a concept to detailed design. Decisions taken during the process and reasons behind them are discussed. In second part requirements of regulations for said aircraft’s landing gear are summarized and forces acting on the landing gear are calculated. This calculation is followed by a strength analysis of critical parts. Analysis of composite body of the ski carried out with a use of FEA and optimalization of its composite material layout is presented in a more detailed way.
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Study of mechanical and thermal properties of nanoparticle-reinforced composites
Németh, Gergely ; Mathis, Kristián (advisor) ; Lukáč, Pavel (referee)
Title: Study of mechanical and thermal properties of composites reinforced by nanoparticles Author: Gergely Németh Department: Department of Physics of Materials Supervisor: RNDr. Kristián Máthis, Ph.D. Abstract: In the present work the deformation behavior of magnesium-based alloy AZ31 reinforced by SiC nanoparticles which was produced by horizontal continual casting is studied. Tension tests in the room temperature, compression tests in the temperature range of 20řC-300řC have been preformed. Samples was with two different orientation. Deformation strain rate was 10-3 s-1 . Simultaneously, the acoustic emission is recorded and studied. The mechanisms of plastic deformation of material are discussed mainly in term of mechanical twinning. Dependence of deformation behavior in compression on temperature is analyzed. The microstructure of original and deformed material is also studied. Keywords: magnesium alloys, composit material, mechanical twinning, metals with hexagonal structures.
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Behaviour of Sandwich Composite Panels under Bending Stress
Zlámalová, Pavlína
This paper presents verification of the behaviour of FRP-based composite beams under four-point bending test, which. were made in different configurations to describe the effect of the laminate surface layer and the effect of the joint between the beam at the web and the flange on the resulting behaviour of the structural element. Its application is mainly in the field of aggressive environments (e.g. wastewater treatment plants), where these materials show higher durability and stability compared to reinforced concrete. The optimum use of composite materials results in a composite beam with relatively high stiffness, load-bearing capacity and high resistance to aggressive environments at very low self-weight. As a result of the experiments, the behaviour of the composite beam, the influence of the laminate surface layer and the determination of the physical-mechanical parameters of the sandwich structure are described.
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