This diploma thesis deals with a design of a stationary engine connecting rod, its stress analysis and its safety factors. The thesis is divided into several parts. At the beginning there is a short research of connecting rods construction and a description of the engine. Then the main dimensions of a piston group and a connecting rod are defined and its 3D model is created. Next, the calculations of forces acting on the connecting rod in the crankshaft mechanism, are carried out. The following part deals with a stress analysis of the model created by MPK. From the obtained stress results, the safety factor at fatigue limit in chosen places of the connecting rod is calculated. In the conclusion, the results of the stress analysis and set safety factor level, are recapitulated.

Diploma thesis deals with the exhaust system able to pass emission restrictions Stage IV. How emissions are produced as well as how could be minimized is described. Analysis of components lay out necessary to AdBlue injection is mentioned. Main part of this paper handle with given design of exhaust system combining diesel particulate filter, as well as filters required to reduce nitrogen oxides. Strength analysis covering vibrations, welds, fatigue and life is concluded. Thesis is made for Zetor Tractors a.s. purposes.

The goal this work is solve the case of customer complaint. The solved part is loaded by high pressure and extend the service life will be considered a number of possible solu-tions. Among them will be selected to best in terms of technical, economic, and rate of delivery.

The aim of the diploma thesis is to study fatigue properties of EN AW-2618A aluminium alloy produced by selective laser melting (SLM). S-N diagrams of reference alloy and SLM material depending on manufacturing conditions were constructed. Reference alloy had the same chemical composition as the SLM material, but it was made by traditional technology (by extruding). While testing, acoustic emission (AE) and resonant frequency of loading was monitored. Fractographic analyses of fracture surfaces were performed. It was found, that SLM material has significantly worse fatigue performance. Fatigue properties are strongly dependent on SLM process parameters settings and precise observance of procedure. The most significant differences in cyclic degradation were found in the length of the stages of fatigue. The more homogeneous the material is, the longer the nucleation stage compared to the total lifetime is. The main source of AE in case of the reference material is plastic deformation on the tip of the crack. For SLM testing, stronger acoustic activity was recorded, because brittle fracture of the material between discontinuities, which is stronger AE source, is more frequent.

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.

This master’s thesis focuses on the fatigue properties of spring steel 54SiCrV6. The theoretical part deals with the properties and use of spring steel and metal response to cyclic loading. The main aim of this work was to obtain the basic mechanical properties as well as the hight cycle fatigue data. Additional metallographical evaluation of microstructure.

Coiled springs are one of the important parts providing comfort during driving vehicles. These components highly demand on their fatigue life. This thesis examines the possibility of the influence of surface quality of a spring wire during production process of coiled springs on their mechanical properties and durability.

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.

This work deals with fatigue life and fractographycal analysis of plasma-nitrided and virgin specimen made of the low-alloy high-strength steel. Specimens were subjected to in-phase combined bending-torsion loading. The work is focused on three groups of problems. The first group of problems was associated with the fatigue life and its prediction. The objective was to examine a relationship between the presence of the nitrided layer and fatigue life. The application of surface layers has significantly improved the fatigue life in the high-cycle region. An extended comparison between classical and advanced multiaxial criteria was performed. Criterions proposed by Marin and Matake were found to be most precise. The second objective of this work was to examine a relationship between the loading ratio ( is the bending amplitude and is the torsion amplitude ) and the fracture surface topography in the highcycle fatigue. Properties of fracture surfaces were quantified by many roughness and fractal parameters. Many roughness parameters start to incrise rapidly above a critical value of the loading ratio zc = 0,5. The last part of this work deals with the fractographical analysis of fish-eye cracks that were formed in plasma-nitrided steel specimens under symetrical bending, symetrical torsion and biaxial in-phase bending-torsion combinations.

This thesis studies the possibilities of exploiting the acoustic emission method as a tool for more detailed identification of the radial bearings damage formation. The work includes comparison of different evaluation methods in laboratory tests. Applied couplant between the contact sensor areas and sensing surfaces is also taken into account. The practical part includes the presentation of the experimental station and structural adjustments made. The main part of the work comprises the examples in detail of three types of experimental tests that simulate the possible failure of bearings and their manifestation in the sensing signal. Testing methodology developed with recommended values for setting common AE signal measurement, vibration and temperature is a part of the thesis, too.