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Proposal of topology of piezoceramic composite sensor
Dostal, Vojtěch ; Ševeček, Oldřich (referee) ; Majer, Zdeněk (advisor)
This master thesis deals with design and numerical modelling of piezoceramic sensor, which is placed on a rail, in order to generate electrical energy, which can be used for wireless monitoring of railway traffic and to monitor the condition of the railway. The thesis is divided into three parts. Theoretically background of piezoelectric energy harvesting is described in first part, where some previous application of piezoelectric generator in railway area are shown. In the second part, parametric analysis of numerical model is performed, which directly leads to finding best location on a rail, where piezoelectric generator should be placed. For this analysis the homogenized model of MFC sensor was used. Results of the numerical model were then compared with the results of the conducted experiment. The third part presented own design of piezoceramic sensor, which is placed onto most suitable location on a rail. Results from numerical analysis shown eligibility of using piezoceramic sensor to monitor the railway traffic.
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Metallization of technical plastics for lightweight traffic components with reduced fuel consumption
Sanetrníková, Dominika ; Boušek, Jaroslav (referee) ; Šimůnková, Helena (advisor)
The beginning of this thesis is dedicated to polymeric materials, which include plastics an composites. Plastics are shortly divided into two groups, thermoplastics and thermosets. The following part is the use of plastics and composites in traffic industry and briefly this work focuses on techniques of recycling of this materials. This work also focuses on the techniques of thin film deposition, electroless plating, electrodeposition as well and plating in the vacuum environment. special techniques of thin film deposition are also mentioned shortly. The coatings of polymer including cleaning and surface activation is introduced using various techniques including plasma treatment. The surface treatment of polyetheretherketone (PEEK) is included too. The final part describes performed experiments and discussion of results.
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Materials for space technology
Bačová, Alena ; Tříska, Václav (referee) ; Petrásek, Miloslav (advisor)
This master´s thesis is dealing with an analysis of materials used for space technology. The thesis is divided into eight main parts. The first part defines space technology. The second part introduces the issue of designing satellites and planning the space mission. The third part describes the effects of the environment on space technology before launch, during launch and flight, in space, and during atmospheric entry. The fourth part introduces the most used standards in Europe for the space industry. The fifth part analyses materials and their application in the space industry. The sixth part provides an overview of aerospace materials tests. The seventh part analyse processes and damage of material during and after the impact of a small object. The last part is devoted to the preliminary design of the device for a more accurate analysis of the behaviour of the material during the impact of a small object.
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Design of Wing and Landing gear for TST 14 MC Glider
Štěpánek, Jan ; Šošovička, Róbert (referee) ; Juračka, Jaroslav (advisor)
Modification of TST-14 MC glider, calculation of flight envelope, distribution of lift on the wing, calculation of loading cases of the wing, strength check of choosen construction nodes, design of the landing gear retraction mechanism, setting up loading of landing gear according to ULKM, strength check of landing gear
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Controlled heating of Composite Material
Fajkus, Martin ; Macháň, Ladislav (referee) ; Šteffan, Pavel (advisor)
The supposed thesis considers problem of heating of composite material for outdoor application. Basement of thesis is analysis of submitted sample of composite material. Measured values of composite material were compared and evaluated and than acceptable samples were choosen for next application. Part of thesis is creation of measuring software for analysis of sample. Other part of thesis is realization of equipment of control unit for heating of composite material. Control unit makes it possible to regulate heating and to set up parameters from computer.
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Sandwich structure analysis using Finite Element Methods
Bucňák, Ondřej ; Schoř, Pavel (referee) ; Mališ, Michal (advisor)
This bachelor’s thesis focuses on the analysis of material model core sandwich structures. The behavior of the sandwich core is simulated using Finite Element Method (FEM) in programs MSC.Patran/Nastran. The first part deals with describing the properties of sandwich structures and its components. There are presented examples of the application of sandwich structures. The next section describes the elementary material models. In the last part of bachelor’s thesis is performed FEM analysis of material model sandwich foam core and comparison to the results with the four-point bending test.
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Metal Matrix Composites Prepared by Powder Metallurgy Route
Moravčík, Igor ; Lapin, Juraj (referee) ; Skotnicová, Kateřina (referee) ; Dlouhý, Ivo (advisor)
Ve všeobecnosti, poznatky o design slitin, jejich výrobě a výběru legujúcich prvků sú omezené na slitiny s jedním základním prvkem. Tento fakt ale výrazně limituje možnosti a volnost výběru prvků pro dosáhnuti speciálních vlastností a mikrostruktur. V poslední dekádě se ukázalo, že materiálová věda a inženýrství nejsou ještě zdaleka prozkoumané v důsledku objevu nové třídy materiálů nazvané vysoko entropické slitiny (HEA high entropy alloys). Jejich objev upoutal pozornost vědecké komunity. Základní koncept pro jejich design je, že namísto jednoho, nebo dvou základních prvků obsahují minimálně 5 prvků v podobných atomových koncentracích. V posledních letech se objevila skupina materiálů odvozená od HEA, nazvaná slitiny so střednou entropii (MEA medium entropy alloys). Na rozdíl od HEA ale obsahují 3, nebo 4 prvky. Táto práce je věnovaná studiu přípravy a charakterizaci HEA, MEA a jejich kompozitů s pomocí metod práškové metalurgie. V této práci byli dohromady zkoumány tři kompozice: AlCoCrFeNiTi0.5, Co1.5Ni1.5CrFeTi0.5 a CoCrNi, kompozity s kovovou matricí (MMC metal matrix composites) vyztužené částicemi B4C s CoCrNi jako matricí. Hloubková mikrostrukturní a mechanická analýza těchto materiálů byla provedena pomoví metod rastrovací a transmisní elektronové mikroskopie spojené s tahovými a ohybovými zkouškami. V průběhu celé studie se objevovaly problémy s kontaminací kyslíkem, co se projevilo vznikem značného množství oxidů v připravených materiálech. U Slitiny AlCoCrFeNiTi0.5 byla naměřena tvrdost přesahující 800 HV. Její houževnatost ale byla velice omezena. V její mikrostruktuře byly identifikovány částice in-situ TiC v důsledku přítomnosti organického, anti-aglomeračního činidla (metanolu) v mlecí misce. Tato reakce může být použita v budoucnu k přípravě MMC se záměrnou disperzí TiC. Na druhé straně, slitina CoCrNi ukázala vysoké hodnoty tažnosti (26%) a meze pevnosti přes 1000 MPa. Mikrostruktura obsahovala majoritní FCC fázi s BCC precipitáty. Tahle slitina byla z důvodu vysoké tažnosti zvolena pro přípravu kompozitu s výztuží B4C. V průběhu slinování ale došlo k reakci mezi přítomným Cr a B4C, které výsledkem byl Cr5B3 borid. Tento kompozit mel pevnost v tahu 1400 MP a extrémne jemnozrnnou strukturu. Celková tažnost ale klesla na 1.9 %. Slitina AlCoCrFeNiTi0.5, která mela strukturu složenou jen z FCC tuhého roztoku dosáhla nejlepší kombinaci mechanických vlastností s pevností přesahující 1300 MPa a dostatečnou tažností 4%. Prášková metalurgie se ukázala jako vhodná metoda pro přípravu HEA a MEA slitin a jejich kompozitů, s dobrou kombinací pevnosti a tažnosti. Tato metoda dovoluje měnit mikrostrukturní parametry připravených materiálů jednoduchou úpravou parametrů procesu.
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Design of laminate handlebars for mountain bikes
Hanák, Jiří ; Ševeček, Oldřich (referee) ; Polzer, Stanislav (advisor)
This bachelor’s thesis describes design of laminate handlebars for mountain bikes. The first part describes the mechanical properties of composite materials, with the emphasis on fiber composites. The algorithm for acquiring material characteristics of fiber composite by analytical method is presented. In the next part, it is shown how to control the direction of fibers in lam-inate in the finite element calculations and its impact to resulting stresses in the material. The aim of the last part is design geometry model of laminate handlebars for mountain bikes with following stress – strain analysis by FEM and software ANSYS. The analysis is performed for static loading.
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Application of a reusable vacuum membrane for production of fiber reinforced plastics
Talavášek, Václav ; Zouhar, Jan (referee) ; Gregor, Lukáš (advisor)
The thesis focuses on the manufacturing process of the composites with fiber reinforcement and polymer matrix. The theoretical part contains a description of conventional manufacturing processes. The experimental part of the thesis was based on the design modification of an old convention mold. The aim was to make design changes for the usage of a vacuum membrane. On the mold were made several tests. The goal was to find out the design faults of the mold. The next chapter focuses on the economic comparison of the conventional process and the reusable vacuum membrane process. The last chapter focuses on the design of a new mold, which is going to be utilized for mass production.
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