National Repository of Grey Literature 196 records found  1 - 10nextend  jump to record: Search took 0.02 seconds. 
Thermomechanical fatigue of nickel-based superalloys
Pech, Filip ; Škorík, Viktor (referee) ; Šulák, Ivo (advisor)
The main objective of present bachelor thesis is to compile literature review of thermomechanical fatigue of nickel-based superalloys. Superalloys were developed to work at high temperatures, where sufficiently high strength, oxidation resistance, creep resistance, and resistance to other high temperature adverse effects have to be ensured. Superalloys are despite efforts to find alternatives still widely used and therefore it is necessary to know their properties and limitations. The present review compiles basic overview of nickel-based superalloys based on specialized publications. First of all, classification of Ni-based superalloys, chemical composition, along with an overview of the most important phases, which are affecting properties of superalloys were studied in detail. The second chapter describes basics of isothermal fatigue of materials, its definition, description of mechanism and basic fatigue life curves. Penultimate chapter of this literature review deals with thermomechanical fatigue and the structure of text is similar to chapter about isothermal fatigue. In the last chapter is given an overview of thermomechanical fatigue of different types of nickel-based superalloys.
Mechanical properties Al-alloy EN AW 7020 at increase temperatures
Slouka, Marek ; Kohout, Jan (referee) ; Věchet, Stanislav (advisor)
The master’s thesis deals with high strength aluminium alloys AlZn4Mg (EN AW 7020). This alloy is used for high strength, low density, a good corrosion resistant and a good weldability in protective atmospheres. At first this thesis is described to aluminium alloys, ways of manufacturing and history. Next this thesis mainly deals with wrought aluminium alloys, heat treatment this alloys and alloys Al-Zn-Mg. Tensile tests were made of alloys EN AW 7020 at room temperature and increased temperature. Next this alloy was made of fatigue test and metallographic analysis. The model was construct. This model describe to behaviour alloy at increased temperature and this model was compared with measure values. This thesis describe to behaviour of study alloy at room temperature and increased temperature.
Fatigue evaluation using electromyography
Mošnerová, Jitka ; Chmelař, Milan (referee) ; Janoušek, Oto (advisor)
The aim of the diploma thesis is the design and implementation of methods for detecting fatigue in electromyogram (EMG). At first is done a literature review on the topic of fatigue detection in electromyography (EMG). Measurement of fatigue-induced changes in the EMG signal is performed on ten subjects using the Biopac ©. Next is in the thesis solved the selection of the optimal methods of evaluating the fatigue-induced changes in EMG recording using statistical testing. In the final part of the thesis is discussion on the results of statistical testing, creation a user interface in Matlab © and comprehensive instructions for laboratory focused on the topic of fatigue in the EMG signal.
Kinetics of Short - crack Growth in Superduplex Steel
Bártová, Lenka ; Pantělejev, Libor (referee) ; Polák, Jaroslav (advisor)
The fatigue life and the kinetics of short crack growth in specimen of austenitic-ferritic duplex steel cycled with constant stress amplitude and different mean stresses is studied. Fatigue life was determined on smooth cylindrical specimens. Strain amplitude and mean strain were recorded. Short crack growth was studied in cylindrical specimens with a shallow notch. Cyclic straining was interrupted and crack length was measured using an optical microscope mounted on the testing machine. Crack length and crack growth rates were evaluated. The effect of the mean stress on the rate of short cracks and fatigue life were discussed.
Assesment of assembling inaccuracy on the coil spring lifetime
Stavárek, Václav ; Hadaš, Zdeněk (referee) ; Lošák, Petr (advisor)
This bachelors thesis is focused on helical compression springs with rectangular wire cross-section. In cooperation with an unnamed company it examines few possible causes of their failure rate. This thesis also includes experimental measurement of change of the spring stiffness after it underwent a high number of cycles.
Design of concrete structures with FRP reinforcement
Januš, Ondřej ; Girgle, František (referee) ; Štěpánek, Petr (advisor)
The diploma thesis presents design of construction with FRP reinforcement. Including design process of cross-section with FRP reinforcement exposed to bending moment and shear force at ultimate limite state according to given standards and guidelines. Long term physical and mechanical properties of FRPs are taking into account. There are also compared load capacities of cross-section exposed to combination of bending moment and axial force, which were designed according to mentioned standards. In another part of diploma thesis there is a design of construction (precast gatehouse) with FRP reinforcement and steel reinforcement with ordinary and lightweight concerete.
Asphalt mixtures with high resistance against cracks
Stromecký, Roman ; Šperka, Pavel (referee) ; Dašek, Ondřej (advisor)
In this bachelor's thesis were suggested two kinds of asphalt mixtures. The first one contains conventional asphalt binder and the second one Crumb Rubber modified Bitumen. The aim of this thesis is a comparison of stiffness and fatigue characteristics of these two mixtures by two-point bending test on truncated wedges. There will be also an evaluation of the impact of an asphalt addition of the Crumb Rubber modified Bitumen in one of these mixtures.
Overhead travelling crane 125t
Peprník, Pavel ; Zimola, Lubomír (referee) ; Pokorný, Přemysl (advisor)
This diploma thesis deals with the assessment of drafted steel construction of overhead travelling crane by using finite element method. The crane’s lifting capacity is 125t/32t. It is going to be placed in hall of Slovácké strojírny, a. s. in Uherský Brod. Span of the crane is 25.8 meters, wheelbase is 6.7 meters and lifting height is 17 meters. My work contains analysis and assessment of crane construction with a load of fatigue according to ČSN 27 0103.
Design and evaluation of asphalt rubber mixture for pavement binder course
Musílek, Lukáš ; Telecký, Jiří (referee) ; Kudrna, Jan (advisor)
The design of asphalt concrete for binder courses with high-viscosity asphalt rubber and low-viscosity asphalt rubber is carried out in the diploma thesis. Selected performance tests (low temperature characteristics, stiffness and fatigue) and water sensitivity are performed for these mixtures. Results are compared each other.
Assess the resistance of the main frame casting cat bridge crane with loading capacity 270/63t - 21 m
Olešovský, Michal ; Přikryl, Jaroslav (referee) ; Pokorný, Přemysl (advisor)
The topic of my Diploma’s thesis is a fatigue analyzing and judgmenting of main frame casting cat bridge crane. Use the beam model and thin shell model for comparising. The thesis contains of both of computation model. The loading states results of computation model are attachmented of this thesis. This diploma’s thesis was created for Kralovopolska a.s. company.

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