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Vibration diagnosis of machines during routine tests
Kohutek, Tomáš ; Hammer, Miloš (referee) ; Nahodil, Petr (advisor)
This master thesis deals with the vibration diagnostics of machine vibrations during unit tests in industrial company Siemens Electric Machines s.r.o Drásov. In the master thesis is elaborated a design of the diagnostic system which contains selected methods of vibration diagnostics, methology, procedure of measurement and evaluation of measured values. The part of master thesis is also a practical example of measurement on which the mentioned system is tested.
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Methods for reliability analysis
Ptáčková, Ludmila ; Krbalová, Maria (referee) ; Řezníčková, Hana (advisor)
This bachelor thesis deals with methods of reliability analysis. The theoretical part of the thesis describes the most frequently used methods of reliability analysis. Subsequently, one of these methods was selected, namely the FMEA method, and applied in practice. As part of the practical part of the work, SCHOTT CR, s.r.o. In Lanskroun, PFMEA has been updated to the drilling process for a specific product. At the end of the thesis is mentioned the possibility of using APIS IQ program for creation of PFMEA writing.
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Probabilistic analysis of reinforced concrete bridge made of I-73 girders
Nezval, Michal ; Šomodíková, Martina (referee) ; Lehký, David (advisor)
Many older bridges on the highways and roads in the Czech republic and all arend the world have been designed by codes, which are distinct of currently valid codes. Considering current codes, it is possible to set load bearing capacity in few different ways. In presented diploma thesis nonlinear finite element analysis using deterministic methods is compared with fully probabilistic nonlinear finite element analysis. Girder I-73 is analysed. Also the influence of degradation processes and following corrosion of reinforcement is taken into account, when load capacity is predicted for residual service life.
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Stochastic analysis of shear failure of reinforced concrete beams
Kucek, Martin ; Doležel, Jiří (referee) ; Novák, Drahomír (advisor)
The diploma thesis is focused on a solution of the load reaction of the bridge construction from girders KA-73. Proposal methods of the nonlinear analysis by means of final elements on the stochastic and deterministic level are used for the solution of the load reaction. A simulation technique Latin Hypercube Sampling is used within the stochastic analysis. A material degradation in the form of the trussing corrosion is solved with the expected decrease of the construction lifetime. The conclusion of the thesis contains an evaluation of initial quantities of material parameters for the load reaction of the construction in the form of the sensitivity analysis.
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Power Inverter Online Diagnostics
Knobloch, Jan ; Chlebiš,, Petr (referee) ; Drábek,, Pavel (referee) ; Klíma, Bohumil (advisor)
This doctoral thesis focuses on the problems of IGBT failure prediction in pulse converters using measurable changes of selected parameters (so--called trending variables) being influenced of transistor degradation during aging. Firstly the state--of--the--art in this field is presented in the dizertation. The description of designed and constructed automated measurement stand follows, enabling monitoring and recording of switching processes during accelerated aging. Further the problems of high--bandwidth measurement of electrical quantities during IGBT switching are described. Especially the problems of current sensing are analyzed and the most suitable sensor is selected. The data recorded using the developed apparatus served to identify potential trending variables allowing the failure prediction. Here the dependence of trending variables on aging and on parasitic influences (current, temperature, voltage) had to be distinguished. Finally the evaluation of trending variables is performed. Their insignificant sensitivity on accelerated aging is shown which complicates their practical implementation for the purpose of failure prediction.
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Hodnocení spolehlivosti lidského činitele v procesní průmyslu
Výzkumný ústav bezpečnosti práce, v.v.i.
Today, the human factor has become a common theme in many sectors of human activities. These include the military sector and the military, because improper use of weapon systems or their conscious abuse is considered a very serious threat. In terms of civilian operations are mainly operating nuclear power plants, chemical plants, air transport, but also health, where great emphasis is placed on reliability (and accuracy) of man.
Fulltext:  PDF
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Methodology of highly reliable systems design
Straka, Martin ; Gramatová, Elena (referee) ; Racek, Stanislav (referee) ; Kotásek, Zdeněk (advisor)
In the thesis, a methodology alternative to existing methods of digital systems design with increased dependability implemented into FPGA is presented, new features which can be used in the implementation and testing of these systems are demonstrated. The research is based on the use of FPGA partial dynamic reconfiguration for the design of fault tolerant systems. In these applications, the partial dynamic reconfiguration can be used as a mechanism to correct the fault and recover the system after the fault occurrence. First, the general principles of diagnostics, testing and digital systems dependability are presented including a brief description of FPGA components and their architectures. Next, a survey of currently used methods and techniques used for the design and implementation of fault tolerant systems into FPGA is described, especially the methods used for fault detection and localization, their correction, together with the principles of evaluating fault tolerant systems design quality. The most important part of the thesis is seen in the description of the design methodology, implementation and testing of fault tolerant systems implemented into FPGAs which uses SRAMs as the configuration memory. First, the methodology of developing and automated checker components design for digital systems and communication protocols is presented. Then, a reference architecture of a dependable system implemented into FPGA is demonstrated including several fault tolerant architectures based on the use of partial dynamic reconfiguration as the mechanism of fault correction and the recovery from it. The principles of controlling the reconfiguration process are described together with the description of the test platform which allows to test and verify the design of fault tolerant systems based on the methodology presented in the thesis. The experimental results and the contribution of the thesis are discussed in the conclusions.
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Methodology of highly reliable systems design
Straka, Martin ; Kotásek, Zdeněk (advisor)
In the thesis, a methodology alternative to existing methods of digital systems design with increased dependability implemented into FPGA is presented, new features which can be used in the implementation and testing of these systems are demonstrated. The research is based on the use of FPGA partial dynamic reconfiguration for the design of fault tolerant systems. In these applications, the partial dynamic reconfiguration can be used as a mechanism to correct the fault and recover the system after the fault occurrence. First, the general principles of diagnostics, testing and digital systems dependability are presented including a brief description of FPGA components and their architectures. Next, a survey of currently used methods and techniques used for the design and implementation of fault tolerant systems into FPGA is described, especially the methods used for fault detection and localization, their correction, together with the principles of evaluating fault tolerant systems design quality. The most important part of the thesis is seen in the description of the design methodology, implementation and testing of fault tolerant systems implemented into FPGAs which uses SRAMs as the configuration memory. First, the methodology of developing and automated checker components design for digital systems and communication protocols is presented. Then, a reference architecture of a dependable system implemented into FPGA is demonstrated including several fault tolerant architectures based on the use of partial dynamic reconfiguration as the mechanism of fault correction and the recovery from it. The principles of controlling the reconfiguration process are described together with the description of the test platform which allows to test and verify the design of fault tolerant systems based on the methodology presented in the thesis. The experimental results and the contribution of the thesis are discussed in the conclusions.
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Evaluation of pasive detectors in intrusion and hold-up alarm systems
Kalivoda, Petr ; Hart, Jan (advisor) ; Libich, Ladislav (referee)
Thesis deals with passive safety elements . The issue is dealt with in the theoretical part and
a practical part . In the theoretical section provides information used for introduction and its
current development . The practical part deals with the principles of magnetic -synaptic
contacts , their reliability and proper functioning . It adds an option for simple - holding .
Shown are the practical experiments from laboratory measurements to clarify the issue of
magnetic contacts and compare actual values with the theoretical values indicated by the
manufacturer . Finally, we evaluated the results of the work
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Reliability of telephone dialer in I&HAS
Beneš, Petr ; Votruba, Zdeněk (advisor) ; Kolářík, Jaromír (referee)
The aim of this study is to evaluate and practically verify the reliability and safety of communicators from the perspective of a potential attack on the security system connected through a telephone line to the ARC (Alarm Receiving Centre). The Intruder and Hold-up Alarm System (I&HAS) itself without being connected to the ACR, is actually an acoustical optical signaling device which does not deal with the comprehensive protection of property and may not fully discourage a potential offender from entering a guarded object. The theoretical part describes the individual transmission paths of the access telephone network, the principles of communication between the I&HAS and ARC, the connection systems and their signaling. The pitfalls of the transmission paths and the possibility of their attack are also defined. The practical part describes the implementation of one of the possible techniques of attack in detail.
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