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Physical axle model for dynamic tests
Bělunek, Matěj ; Dočkal, Aleš (referee) ; Mazůrek, Ivan (advisor)
The aim of this thesis is the design of a physical axle test station, along with a virtual dynamic model, with the purpose of vehicle suspension tests. The axle, or half-car, model is the answer to the inaccuracies of the most widely utilized suspension model, and the high cost of the full vehicle testing. The motivation for the new test station and its virtual model is the prospect of accurate, quick and effortless testing and optimization of the vehicle suspension characteristics. The existing solutions in most cases substitute actual suspension elements (axle) and wheels with auxiliary parts leading to a departure from reality. The design of the new test station is based on the analysis of current physical model solutions and in accordance with set requirements. The tester substitutes the vehicle Škoda Fabia I Hatchback and utilizes its actual rear axle including suspension elements. The assembled rig, or rather its functionality, is successfully experimentally verified. The created virtual dynamic model, using ADAMS software, is identified against the designed test station, while the obtained simulation results are compared with the experiment data. Meeting the experiment predictions and virtual model results validates the tester’s ability to sufficiently reflect real car suspension behaviour and it is ready for further vehicle spring and damping properties testing.
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Modernization of R-mat test stations
Papaj, Lukáš ; Dočkal, Aleš (referee) ; Mazal, Pavel (advisor)
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.
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Localization and identification of damage type of pneumatic drives
Richter, Vladislav ; Dočkal, Aleš (referee) ; Mazal, Pavel (advisor)
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.
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Methodology for remote diagnostic of the automotive shock absorbers
Halama, Jakub ; Dočkal, Aleš (referee) ; Klapka, Milan (advisor)
The diploma thesis deals with the application of acoustic methods for evaluating the technical condition of the shock absorbers. Analysis of acoustic radiation during damping operation leads to the definition of a new non-contact diagnostic methodology that can determine the condition of the shock absorbers. The first part of the thesis focuses on the noise radiation of the shock absorbers, which is caused by discontinuous dumping. Further, the methods for the noise source localization available at The Institute of Machine and Industrial Design are described – with their functionalities, advantages and limitations. Based on all the information, an appropriate method is selected and used in the experimental part of this work. Then, aeration and removing the full volume of oil with damage of the shock absorber tube are caused (induced) on several types of the shocks. Noise radiation is measured by a microphone array and by a sound meter; the acoustic maps, frequency spectra and the synchronous filtration graphs are calculated from the measured data. From the differences in the acoustic radiations of each shock condition, a suitable diagnostic criterion for a specific shock absorber is defined. The final part discusses obtained results. Based on these results, a general diagnostic methodology, applicable to any type of shock absorber, is formulated.
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The study of magnetorheological shaft seal
Pavlíček, Dušan ; Dočkal, Aleš (referee) ; Kubík, Michal (advisor)
This thesis deals with the experimental study of magnetorheological shaft seal. The purpose of this diploma thesis is to describe the operating parameters of rotational magnetoreological shaft seal. In thesis, the effects of magnetic field and shaft speed on the pressure resistance and braking torque are described. Operating parameters were measured by an experimental device. Research has shown that the magnetoreological seal is characterized by a high pressure resistant. Disadvantages are the high braking torque and leakage of carrier oil from the magnetorheological fluid. These problems have been solved by a new design of magnetic circuit, that has been identified as a magnetoreological gradient pinch seal (MRGPS).
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Experimental chamber for testing of special materials using SLM technology
Malý, Martin ; Dočkal, Aleš (referee) ; Koutný, Daniel (advisor)
The thesis deals with the influence of process temperature and pressure on 3D printing using Selective Laser Melting. The aim of the thesis is the design, manufacture and testing of the experimental chamber for SLM 280HL from company SLM Solutions. The main task of the experimental chamber is to increase the temperature of the preheating of the powder bed from the original 200 °C to at least at 400 °C. The device will be used to investigate the influence of high process temperature on the properties of printed materials. The thesis also deals with the design of the powder applicator for elevated temperatures.
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Mobile tester of suspension automotive wheels
Novák, Petr ; Dočkal, Aleš (referee) ; Mazůrek, Ivan (advisor)
This diploma thesis deals with the constructional design, followed by the manufacturing of the tester for non-invasive diagnostics of cars shock absorbers. It is a resonant adhesive tester with 3 mm lift of measuring platform, in contrast with standardly manufactured testers with 6 mm lift. By reducing lift of measuring platform is eliminated failure of EUSAMA methodology for problematic vehicles. In the thesis are also included verifications of tester function and comparative measurements with standardly manufactured tester.
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Analytical Methods in Motorsport
Růžička, Bronislav ; Dočkal, Aleš (referee) ; Čejka, Václav (referee) ; Karpíšek, Zdeněk (referee) ; Mazůrek, Ivan (advisor)
This dissertation is focused on proposal for simplified data analyze approach for sport-car vehicle dynamic evaluation with relationship to possibility for qualified estimation of set-up parameters influence for overall vehicle performance. In common practice can be usual overlapping effect caused by concurrent changes of car setup elements if performed in the same moment with resulting in not correct or hardly definable process determination for evaluation and decision about next steps in car development. For analyze of these multidimensional data is then chosen process with approach by Linear Regression Model (LRM). In dissertation is proposed basic philosophy with concern on specificity of car vehicle dynamics, performed experiment with defined inputs including analyze and interpretation method of obtained outputs. This methodic take into account also possibility for general application of multidimensional data analyses not only in motorsport, but as well for dynamic behavior diagnostics of technical systems where finding of optimal running condition depends on multi-parametric setup whose combination must reflect often changes of outer conditions too.
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Design of 3D printer for high strength materials
Žlebek, Michal ; Dočkal, Aleš (referee) ; Koutný, Daniel (advisor)
Thesis deals with FDM 3D printing method and testing capabilities of optimum printing conditions for different materials. The aim of this work is to design and manufacture of experimental device that enables printing to investigate these conditions. A device designed in this work was named UK3DP and allows dual color object printing with maximum dimensions of the square base of 150 mm and a height of 150 mm. Before printing, the user can set almost all parameters affecting the printing process, including air temperature in heated chamber that is part of it. To verify the functionality several materials are tested, including ABS, PC and PEI. It also describes basic verification of the influence of selected parameters on the print result. Performs tensile tests confirming the influence of ambient temperature during printing on the quality of fiber connections, examines the final quality of the surface for each layer height and compares the resulting deformation of printed objects with other printers. The result of this work is a 3D printer capable of testing printing conditions for both existing and new types of materials with a range of user adjustable parameters.
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