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Fatigue damage mechanism of MAR-M 247 superalloy
Jíša, Jakub ; Štěpánek, Roman (referee) ; Pantělejev, Libor (advisor)
The thesis deals with the fatigue resistance of material MAR-M 247 at temperatures of 650 °C, 800 °C and 900 °C. Based on the results obtained, curves of durability ("S/N curves") were drawn and the effect of temperature on the fatigue behaviour of nickel-based superalloys MAR-M 247 and IN713 LC was evaluated. Fractographic analysis was used to examine the failure mechanism and the effect of casting defects on the fatigue crack initiation.
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The fatigue life of steel specimens under axial, torsional and combined axial-torsional loading
Mička, Jan ; Horníková, Jana (referee) ; Slámečka, Karel (advisor)
The master’s thesis deals with the fatigue life prediction under multiaxial cyclic loading. First, the fatigue process is discussed and the methods for fatigue life prediction under uniaxial and multiaxial loading are described. In the practical part, the accuracy of selected criteria is assessed based on experimental data obtained on cylindrical samples made of 1.2210 steel that were tested under synchronous symmetric axial-torsion loading. Application of criteria requires to determine the fatigue strength under pure axial and torsional loading.
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Seal Plugs Design for Common-Rail System Pressure Reservoir High-Cyclic Fatigue Testing
Skrutek, Ivo ; Cupl, Zdeněk (referee) ; Ramík, Pavel (advisor)
Tato diplomová práce je zaměřena na řešení problému praskání těsnících kuželů na tělesech railů při zkoušce dlouhodobé životnosti pomocí pulzního vysokotlakého testu. Hlavní částí je analýza vlivu těsnících zátek na namáhání těsnícího kuželu s následným návrhem nové zátky, která bude tvořit stejné nebo podobné zatížení všech komponent při pulzním testu jako vysokotlaká trubka, která se používá v sériové produkci. Další částí je ověření vlastností nové zátky pomocí vysokotlakého pulzního testu.
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Strength control of bicycle crank assembly
Kolenčík, Richard ; Skalka, Petr (referee) ; Burša, Jiří (advisor)
This bachelor thesis is intent on strength-deformation check of bicycle crank assembly. The first part is devoted to check safety of fatigue failure of crank bicycle, which is loaded with combination loading. The second part is devoted on safety analysis of fatigue failure in the case of pedal. Because of low safety´s coefficient is made calculation of high cyclic life of pedal. The last section is devoted to the calculation of maximum deformation of the crank assembly. The analytical calculation was performed by the software Matlab R2012b.
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Fatigue behaviour of AZ31 and AZ61 magnesium alloys after corrosion degradation
Horynová, Miroslava ; Vojtěch, Dalibor (referee) ; Obrtlík, Karel (referee) ; Podrábský, Tomáš (advisor)
Dissertation thesis is focused on evaluation of influence of exposure in 5% salt fog on fatigue behavior of AZ31 and AZ61 magnesium alloy fabricated by squeeze casting method. Microstructure and mechanical properties of experimental materials have been evaluated. The AZ61 alloy was solution heat treated after prior optimization of the heat treatment process based on microstructural characteristics and mechanical properties. Depths of corrosion damage, corrosion rate and mechanism of corrosion of all three experimental alloys have been evaluated. Influence of prior corrosion exposure for 480 and 1000 hours on fatigue behavior of experimental materials was evaluated. Obtained data were compared with data obtained using smooth test specimens. Fractographic analysis was carried out on both smooth and precorroded specimens. Furthermore, influence of aluminium on corrosion and fatigue behavior of tested alloys was defined.
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Strength and lifetime analysis of the hydraulic key lock
Klíč, Jan ; Majer, Zdeněk (referee) ; Vrbka, Jan (advisor)
Theoretical part of this master thesis is focused on the theory of fatigue life. The second part deals with the assesment of static strength the closing flap in front of water turbine. Futher fatigue analysis of the closing flap is performed considering corrosive environment. The aim is to verify the required service lifetime of 50 years.
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Cyclic plasticity and low-cycle fatigue resistance of materials prepared by the ColdSpray method
Brůža, Jaromír ; Šulák, Ivo (referee) ; Zapletal, Josef (advisor)
In the theoretical part, the diploma thesis focuses on Cold spray technology and parameters affecting the efficiency and quality of deposition. Next, there is an introduction to the fatigue process of materials. The theory is concluded with a summary of the current knowledge regarding materials created by Cold spray technology in the field of fatigue. In the practical part, volumetric bodies were created from the material EN AW7075. Specimens for tensile and fatigue tests were cut from the bodies by electrosparking. From the material and powder, metallographic cuttings were created for the determination of porosity using Archimedes’ principle, hardness according to Vickers and evaluation of EDS and EBSD analysis. The basic mechanical properties were determined from the tensile tests and the Wöhler-Basquin parameters were determined from the fatigue tests along with the life curve. Subsequently, a fractographic analysis of fracture surfaces using SEM took place.
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The influence of a computational model of crank train dynamics on engine block load
Charvát, Adam ; Dlugoš, Jozef (referee) ; Drápal, Lubomír (advisor)
This work investigates the influence of the computational model of the cranktrain dynamics on the engine block load around the main bearings depending on the discretization level of the bodies used. Four variants of the computational model of the cranktrain in the Multi-Body System software SIMDRIVE 3D are compared with respect to the load on the main bearings. Based on the obtained loads, a strength analysis of the EA211 series 1,5 MPI mass-production engine block, manufactured by ŠKODA AUTO, is performed, including the influence of pre-stress during the assembly of the cylinder head and bearing caps. To evaluate the results, a fatigue life calculation is performed, and the endurance safety factors in the grooves on the bottom of the engine block are compared.
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Optimalizace podmínek testování turbínových kol na plynových hořácích
Handl, Martin
The thesis describes the topic of turbine wheel testing in terms of high-cycle fatigue in general. It explains specifics of fatigue life testing on engine with real conditions and testing on gas stand with simulated conditions. The main part solves the optimization of conditions simulated by gas stand in relation to the real conditions on the engine.
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