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Pneumatic drives are an integral part of many machinery, with high demands on their reliability. Unfortunately, they sometimes fail, either due to improper production or assembly at the factory or by gradual degradation of moving parts and sealing elements during operation. Current diagnostic methods do not allow localization or identification of the type of damage and do not allow the operator to make a qualified decision. This work deals with the use of acoustic emission for these purposes. On PB type cylinders manufactured by Poličské strojírny a.s., a methodology is introduced which leads to the direct identification or at least localization of selected defects. By implementing this methodology in the final inspection of the production plant, the percentage of exposed pieces of waste will be increased, thus preventing accidents of these faulty pieces during operation.

The purpose of this diploma thesis is to get a better understanding of cold kinetic deposition (cold spray), principles of functioning of this method followed by an evaluation of advantages and disadvantages of cold spray and its comparison to conventional thermal methods and a simple summary of the practical use of cold spray with respect to different materials. Next there is a summary of the properties and uses of frequently applied metals in electrical engineering, aluminium and copper, description of metal corrosion and an understanding of the diagnostic method of acoustic emission. In the practical part, a sample with copper cold spray coating on aluminium substrate was created. Following, this sample was split for corrosion tests, where the split samples were exposed to a corrosive environment for different times of exposure. The extent of corrosion degradation of the samples was evaluated by acoustic emission and metallographic analysis for corrosion-loaded samples for 100, 200 and 300 hours. In the end, an illustrative design of the application of the cold spray technology was created.

The aim of the thesis is to reconstruct obsolete R-mat test stations, which are used for rolling contact fatigue tests of material, which are still of interest from industry. It was necessary to replace the original control electronics with a new industrial computer to allow use modern sensors and automate the entire test process. At the same time, the measurement was supplemented by an acoustic emission method, which can also record the development of damage. Design modifications have been made that allow the installation of all new sensors. The main method for evaluating the tests is vibrodiagnostics, which is supplemented by the acoustic emission method. With the help of several experiments, the shortcomings of the new control system were identified, some parameters were designed, and the main functionality of the modernized R-mat station was verified. According to the proposed parameters and the identified shortcomings, the control system was modified, and a script was created, which is used to evaluate the test. It is still possible to perform rolling contact fatigue tests of the material on the modernized equipment, and thanks to the modernization of the electronics, it is possible to test completely new methods of test evaluation.

Master’s thesis is focused on modification of experimental arrangement for radial ball bearing contact endurance testing so that the diagnostic method of acoustic emission could be applied. There is an assumption that AE method is able to identify damage to bearings in earlier stages than the vibration diagnostics. Design modifications also allow the addition of modern vibrodiagnostic equipment to a system.

This master’s thesis is concerned analysis of signal of acoustic emission. The analysis is based on data of bearing material and real bearings testing, tested in the Axmat stands. The data was run by software Matlab and Python. Below I created plan for identification of damage stage depending on particular AE events. The results are put into diagram. Finally I’m trying to develop the new possibilities of using acoustic emission into practice on the real machines. There could be earlier prediction of a defect of monitored bearings compared to vibrating diagnostic used until now.

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 deformation mechanisms of commercially pure magnesium using advanced in-situ methods were investigated in the present work. Compression and tensile test were done at room temperature. Simultaneously, the neutron diffraction was measured and the acoustic emission was recorded. The microstructure of the deformed material was also studied by means of optical microscopy and electron back-scattered diffraction. These measurements provided information about twin nucleation and growth, microstructure changes and the influence of the orientation of grains on the number of twins and their shape. The values obtained were compared to the Elasto-Plastic Self-Consistent model, which provides information about the activity of deformation mechanisms. We focused on clarifying the influence of twinning activity on asymmetry between tensile and compression deformation.

This work is focused on the study of the relationship between microstructure, texture and deformation mechanisms in aluminum-free magnesium (Mg) alloys. Extruded alloys containing zirconium, zinc, manganese and neodymium (ZK10, MN11, ZN11) in a form of rectangular profiles were deformed at room temperature. Uniaxial tensile and compression tests were performed in the extrusion (ED), transversal (TD) and normal direction (ND). The concurrent acoustic emission (AE) measurement was used in order to study the collective dislocation dynamic and the nucleation of twins. The deformation texture was studied by X-ray diffraction on samples deformed in compression up to different stress levels. Keywords: Mg alloys, deformation tests, acoustic emission, texture