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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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Diagnostic of System Reliability
Bábek, Tomáš ; Pohl, Jan (referee) ; Havlíková, Marie (advisor)
This thesis is oriented to the reliability theory and diagnostics. It involves brief explanation of terms that exists in a branches of technical devices reliability. The next part contains determining the reliability indexes, calculations of probabilities and statistics for electronic devices. I do mention the different methods of reliability diagnostics. The three most used of them are described. First of them is the reliability block model. By this I describe the serial reliability model, the parallel reliability model and the combination of them. Using this method is the simple way to show how each component affects reliability of the whole system. The second method is FMEA (Failure Mode and Effects Analysis) which is used mostly in the begining of the system designing. The third method is FTA (Fault tree analysis) which is one of the classic deductive methods. The FTA method is a graphical reliability model of a given system. By the end of this thesis, process of calculating the failure probability and the other reliability indexes of a given komponent (preamplifier with operational amplifier) is shown.
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Reliability-based structural optimization
Slowik, Ondřej ; Pukl, Radomír (referee) ; Novák, Drahomír (advisor)
This thesis presents the reader the importance of optimization and probabilistic assessment of structures for civil engineering problems. Chapter 2 further investigates the combination between previously proposed optimization techniques and probabilistic assessment in the form of optimization constraints. Academic software has been developed for the purposes of demonstrating the effectiveness of the suggested methods and their statistical testing. 3th chapter summarizes the results of testing previously described optimization method (called Aimed Multilevel Sampling), including a comparison with other optimization techniques. In the final part of the thesis, described procedures have been demonstrated on the selected optimization and reliability problems. The methods described in text represents engineering approach to optimization problems and aims to introduce a simple and transparent optimization algorithm, which could serve to the practical engineering purposes.
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Life-cycle analysis of reinforced concrete bridges
Doležel, Jiří ; Vítek,, Jan (referee) ; Pukl,, Radomír (referee) ; Novák, Drahomír (advisor)
With increasing age of the concrete road bridges, the highly topical question is to determine their reliability and load-bearing capacity level required for the residual life of the structure. Doctoral thesis presents a comprehensive methodology for assessing the reliability of reinforced and prestressed concrete bridges based on non-linear finite element method damage and failure virtual simulations at both deterministic and stochastic levels. Load-bearing capacity values are specified by the structure’s design load capacity estimation by global safety factor methods or they are based on a fully probabilistic load capacity analysis using the direct resistance estimation. For the fully probabilistic calculations, the simulation technique Latin Hypercube Sampling is used.
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Probabilistic reliability and durability analyses of reinforced concrete bridges
Šomodíková, Martina ; Kohoutková,, Alena (referee) ; Sýkora,, Miroslav (referee) ; Lehký, David (advisor)
This thesis deals with the development of a complex methodology for probabilistic analysis of reliability and durability of reinforced concrete structures, especially road bridges. An estimation of load-bearing capacity is carried out using probabilistic methods in combination with the nonlinear finite element method analysis and also with respect to reliability requirements according to standards. The current state of the structure is taken into account based on the mathematical modeling of the degradation processes, such as concrete carbonation, chloride ingress and subsequent corrosion of reinforcement. Then the load-bearing capacity and reliability is predicted over time. Attention is focused on the upgrade of the analytical models for modeling of degradation processes with regard to the effect of mechanical load on the structure or its components, the development of an artificial neural network-based response surface method for efficient approximation of the original limit state function with respect to the accuracy and a minimization the number of simulations, and an interconnection of individual processes and advanced methods in an automatic process.
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Reliability-based structural optimization
Slowik, Ondřej ; Červenka,, Jan (referee) ; Lepš, Matěj (referee) ; Novák, Drahomír (advisor)
Presented PhD thesis deals with reliability-based optimization of structures and problems related to automatization of various algorithms of solution for various reliability-based optimization task definitions. The text presents a general definition of the reliability-based optimization problem, followed by a description of state of the art within the broad field of reliability-based optimization as well as the current state of the art of selected methodology utilized or developed by the author during his work in order to meet objectives of his dissertation. The theoretical part of the thesis is supplemented by a description of developed software tools and by examples of described methodology applications during a solution of practical problems of nonlinear numerical models reliability-based optimization and problems of inverse analysis.
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Productivity and economic performance of small and medium-sized enterprises of manufacturing industry
HRUŠKOVÁ, Václava
This theses deals with productivity and economic performance of small and medium-sized enterprises of chosen sector of manufacturing industry in Czech Republic. The main goal of this thesis is to assess the relation between labour productivity and economic performance in the selected sector of furniture manufacture. Required data are gained from database Albertina. The theses is devided into two sectors. The first part of thesis describes scientific findings about productivity and economic performance.Practical part focuses on analysis of labour productivity and economic performance of chosen companies. The last section of pratical part is devoted to proving the relations between labour productivity and economic performance represented by indicator ROA and indexes of financial health: IN99 and Reliability index. Regression and correlation analysis evaluates described relations from the static and dynamic view.
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Life-cycle analysis of reinforced concrete bridges
Doležel, Jiří ; Vítek,, Jan (referee) ; Pukl,, Radomír (referee) ; Novák, Drahomír (advisor)
With increasing age of the concrete road bridges, the highly topical question is to determine their reliability and load-bearing capacity level required for the residual life of the structure. Doctoral thesis presents a comprehensive methodology for assessing the reliability of reinforced and prestressed concrete bridges based on non-linear finite element method damage and failure virtual simulations at both deterministic and stochastic levels. Load-bearing capacity values are specified by the structure’s design load capacity estimation by global safety factor methods or they are based on a fully probabilistic load capacity analysis using the direct resistance estimation. For the fully probabilistic calculations, the simulation technique Latin Hypercube Sampling is used.
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Probabilistic reliability and durability analyses of reinforced concrete bridges
Šomodíková, Martina ; Kohoutková,, Alena (referee) ; Sýkora,, Miroslav (referee) ; Lehký, David (advisor)
This thesis deals with the development of a complex methodology for probabilistic analysis of reliability and durability of reinforced concrete structures, especially road bridges. An estimation of load-bearing capacity is carried out using probabilistic methods in combination with the nonlinear finite element method analysis and also with respect to reliability requirements according to standards. The current state of the structure is taken into account based on the mathematical modeling of the degradation processes, such as concrete carbonation, chloride ingress and subsequent corrosion of reinforcement. Then the load-bearing capacity and reliability is predicted over time. Attention is focused on the upgrade of the analytical models for modeling of degradation processes with regard to the effect of mechanical load on the structure or its components, the development of an artificial neural network-based response surface method for efficient approximation of the original limit state function with respect to the accuracy and a minimization the number of simulations, and an interconnection of individual processes and advanced methods in an automatic process.
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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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