Numerical modeling of laminated glass structures
Šejnoha Michal; Zemanová Alena; Šejnoha Jiří
2014 - English Laminated glass structures are formed by stiff layers of glass connected with a compliant polymer foil. Due to their slenderness, heterogeneity, and time- and temperature-dependent properties of the interlayer, they exhibit a complex mechanical response that is difficult to capture by single-layer models. The main aim of this work is to develop a finite element model that can describe the behavior of laminated glass units without the need for fully resolved three-dimensional simulations, which lead to unnecessarily expensive calculations. For a geometrically nonlinear description of the behavior of units, each layer is considered to behave according to the Reissner finite-strain beam theory or the Reissner-Mindlin plate theory, complemented with membrane effects and the von Kármán assumptions. The compatibility of independent layers is enforced by the Lagrange multipliers, which proceeds from a refined plate theory due to Mau. The time- and temperature-dependent behavior of the interlayer is accounted for by the generalized Maxwell model and by the time-temperature superposition principle due to the Williams-Landel-Ferry equation. The resulting system is solved by the Newton method with consistent linearization and the viscoelastic response is determined incrementally by the exponential algorithm. By comparing the model predictions against available experimental data, analytical methods and two-dimensional finite element simulations, it is demonstrated that the proposed formulation is reliable and accurately reproduces the behavior of the laminated glass units. As such, it offers a convenient basis to incorporate additional phenomena, such as delamination of glass layers.Laminated glass structures are formed by stiff layers of glass connected with a compliant polymer foil. Due to their slenderness, heterogeneity, and time- and temperature-dependent properties of the interlayer, they exhibit a complex mechanical response that is difficult to capture by single-layer models. The main aim of this work is to develop a finite element model that can describe the behavior of laminated glass units without the need for fully resolved three-dimensional simulations, which lead to unnecessarily expensive calculations. For a geometrically nonlinear description of the behavior of units, each layer is considered to behave according to the Reissner finite-strain beam theory or the Reissner-Mindlin plate theory, complemented with membrane effects and the von Kármán assumptions. The compatibility of independent layers is enforced by the Lagrange multipliers, which proceeds from a refined plate theory due to Mau. The time- and temperature-dependent behavior of the interlayer is accounted for by the generalized Maxwell model and by the time-temperature superposition principle due to the Williams-Landel-Ferry equation. The resulting system is solved by the Newton method with consistent linearization and the viscoelastic response is determined incrementally by the exponential algorithm. By comparing the model predictions against available experimental data, analytical methods and two-dimensional finite element simulations, it is demonstrated that the proposed formulation is reliable and accurately reproduces the behavior of the laminated glass units. As such, it offers a convenient basis to incorporate additional phenomena, such as delamination of glass layers. Keywords: laminated glass; finite-strain Reissner beam theory; Reissner-Mindlin plate theory; von Kármán plate theory; finite element method; Lagrange multipliers; time- and temperature-dependent behavior Available at various departments of the ČVUT. Numerical modeling of laminated glass structures

Laminated glass structures are formed by stiff layers of glass connected with a compliant polymer foil. Due to their slenderness, heterogeneity, and time- and temperature-dependent properties of the ...

Šejnoha Michal; Zemanová Alena; Šejnoha Jiří
České vysoké učení technické v Praze, 2014

Aplikace Ginzburg-Landauova modelu na inhomogenní feroelektrika
Hlinka Jiri; Stepkova Vilgelmina; Mokrý Pavel
2014 - English Theoretical study of ferroelectric domain nanostructures Available at various departments of the ČVUT. Aplikace Ginzburg-Landauova modelu na inhomogenní feroelektrika

Theoretical study of ferroelectric domain nanostructures

Hlinka Jiri; Stepkova Vilgelmina; Mokrý Pavel
České vysoké učení technické v Praze, 2014

Chosen economic and environmental aspects of material resources in construction in the view of sustainability - Tools to assess capability to reduce primary energy demand in housing
Dlask Petr; Anisimova Nataliya; Karásek Jiří
2014 - English Energy use in European housing comprises the greatest part of total energy consumption and is above industry and transport figures. The growing trend in building energy use has made energy efficiency strategy the main concern for energy policies which then involve developing new building regulations and certification processes. The main objectives of the thesis is the estimation of financial funds required to motivate the efficient energy use in housing construction in each EU state, and the definition of the most efficient ways of the investment into energy demand reduction in housing. The objectives were reached by means of the following methods: generalization of existing knowledge, experience and requirements, analysis of foreign practice, mathematical-statistical methods of data evaluation, comparative analysis, value engineering. First of all, the required amount of funds for support programs which would motivate the energy efficiency increase in dwelling houses was estimated on a national scale for different EU countries. After that different direction of the required investment into energy efficiency increasing steps were chosen and assessed within the research taking into account not only environmental but also economic aspect. In the thesis were described the following tools to assess the capability to reduce energy demand of buildings: certification systems, thermal energy balance, embodied energy assessment, quantification of energy savings. None of these tools involves both economic and environmental assessment of energy performance of building. The developed tool (total efficiency assessment) is based on the thermal energy balance, discriminant analysis, and the required investment evaluation. The tool was demonstrated on the basis of fifteen case studies with the following approach: the input data (decrease in final energy demand, in primary energy demand and in CO2 emissions) were derived from each option's energy balance of the building; the options were evaluated in accordance with the ratio between the gained utility and required investment; after that the total efficiency of the options was assessed in a short time period.Energy use in European housing comprises the greatest part of total energy consumption and is above industry and transport figures. The growing trend in building energy use has made energy efficiency strategy the main concern for energy policies which then involve developing new building regulations and certification processes. The main objectives of the thesis is the estimation of financial funds required to motivate the efficient energy use in housing construction in each EU state, and the definition of the most efficient ways of the investment into energy demand reduction in housing. The objectives were reached by means of the following methods: generalization of existing knowledge, experience and requirements, analysis of foreign practice, mathematical-statistical methods of data evaluation, comparative analysis, value engineering. First of all, the required amount of funds for support programs which would motivate the energy efficiency increase in dwelling houses was estimated on a national scale for different EU countries. After that different direction of the required investment into energy efficiency increasing steps were chosen and assessed within the research taking into account not only environmental but also economic aspect. In the thesis were described the following tools to assess the capability to reduce energy demand of buildings: certification systems, thermal energy balance, embodied energy assessment, quantification of energy savings. None of these tools involves both economic and environmental assessment of energy performance of building. The developed tool (total efficiency assessment) is based on the thermal energy balance, discriminant analysis, and the required investment evaluation. The tool was demonstrated on the basis of fifteen case studies with the following approach: the input data (decrease in final energy demand, in primary energy demand and in CO2 emissions) were derived from each option's energy balance of the building; the options were evaluated in accordance with the ratio between the gained utility and required investment; after that the total efficiency of the options was assessed in a short time period. Keywords: assessment; tool; housing; energy demand; economic aspect; environmental aspect; total efficiency. Available at various departments of the ČVUT. Chosen economic and environmental aspects of material resources in construction in the view of sustainability - Tools to assess capability to reduce primary energy demand in housing

Energy use in European housing comprises the greatest part of total energy consumption and is above industry and transport figures. The growing trend in building energy use has made energy efficiency ...

Dlask Petr; Anisimova Nataliya; Karásek Jiří
České vysoké učení technické v Praze, 2014

Patterns in URL
Vaníček Tomáš; Hujer Roman; Molnár Zdeněk
2014 - English This text describes the research on patterns in URL, URL classification and their respective relation. Firstly, motives for the URL classification and patterns in URL are explained. The motives come from topicality of the search engines and the webometrics. The webometrics and the search engines later turn out to be an application of the work results. It is be explained which questions the research should answer, what is the hypothesis and for whom could be the research beneficial.Related technologies such as deep web, semantic web, microformats and search engine optimization are mentioned in a chapter about the current state of scientific knowledge and it is explained how these topics influence the research. More space is dedicated to webometrics as it is a science closely related to the work's topic.The core of the work describes traversing as an alternative of following hyperlinks. Then introduces classification as a generalization of the patterns concept, followed by two experiments. The first experiment confirms the numeric pattern. The second experiment demonstrates way of finding another patterns. The chapter is concluded by a formal description of the concept of pattern in URL.In the end is concluded the scientific contribution of the work and outline possible future work.This text describes the research on patterns in URL, URL classification and their respective relation. Firstly, motives for the URL classification and patterns in URL are explained. The motives come from topicality of the search engines and the webometrics. The webometrics and the search engines later turn out to be an application of the work results. It is be explained which questions the research should answer, what is the hypothesis and for whom could be the research beneficial.Related technologies such as deep web, semantic web, microformats and search engine optimization are mentioned in a chapter about the current state of scientific knowledge and it is explained how these topics influence the research. More space is dedicated to webometrics as it is a science closely related to the work's topic.The core of the work describes traversing as an alternative of following hyperlinks. Then introduces classification as a generalization of the patterns concept, followed by two experiments. The first experiment confirms the numeric pattern. The second experiment demonstrates way of finding another patterns. The chapter is concluded by a formal description of the concept of pattern in URL.In the end is concluded the scientific contribution of the work and outline possible future work. Keywords: hyperlink; URL; pattern; resource; hyperlink classification Available at various departments of the ČVUT. Patterns in URL

This text describes the research on patterns in URL, URL classification and their respective relation. Firstly, motives for the URL classification and patterns in URL are explained. The motives come ...

Vaníček Tomáš; Hujer Roman; Molnár Zdeněk
České vysoké učení technické v Praze, 2014

Method for measuring lens distortion
Pavelka Karel; Řezníček Jan; Mikš Antonín
2014 - English A new method for measuring glass lens distortion based on using distortion-free pinhole lens is proposed, where the measure of the distortion progress is derived by comparing two images of the calibration field given by pinhole lens and glass lens. Such a simple procedure of lens calibration is advantageous as no additional parameters, that could influence the reliability of the estimation, have to be considered. Those additional parameters are usually the elements of EO which in certain camera component configurations highly correlates with the lens distortion characteristics. Furthermore, such an approach based on measuring relative values given by the comparison of two images do not require absolute position of the calibration field targets which reduces additional sources of error given by target surveying. Particularly, the lens distortion variation induced by change in magnification or aperture can be easily obtained. The proposed method for measuring lens distortion is applied in an experimental investigation leading to the confirmation of the validity of the theoretical development. The result of the investigation derives a promising new possibility for accurate lens calibration.A new method for measuring glass lens distortion based on using distortion-free pinhole lens is proposed, where the measure of the distortion progress is derived by comparing two images of the calibration field given by pinhole lens and glass lens. Such a simple procedure of lens calibration is advantageous as no additional parameters, that could influence the reliability of the estimation, have to be considered. Those additional parameters are usually the elements of EO which in certain camera component configurations highly correlates with the lens distortion characteristics. Furthermore, such an approach based on measuring relative values given by the comparison of two images do not require absolute position of the calibration field targets which reduces additional sources of error given by target surveying. Particularly, the lens distortion variation induced by change in magnification or aperture can be easily obtained. The proposed method for measuring lens distortion is applied in an experimental investigation leading to the confirmation of the validity of the theoretical development. The result of the investigation derives a promising new possibility for accurate lens calibration. Keywords: Photogrammetry; Computer vision; Camera calibration; Lens distortion; Pinhole lens. Available at various departments of the ČVUT. Method for measuring lens distortion

A new method for measuring glass lens distortion based on using distortion-free pinhole lens is proposed, where the measure of the distortion progress is derived by comparing two images of the ...

Pavelka Karel; Řezníček Jan; Mikš Antonín
České vysoké učení technické v Praze, 2014

Fire resistance of fibre reinforced concrete floors
Vodička Jan; Welz Markus Jochen; Procházka Petr
2014 - English Available at various departments of the ČVUT. Fire resistance of fibre reinforced concrete floors

Vodička Jan; Welz Markus Jochen; Procházka Petr
České vysoké učení technické v Praze, 2014

Dynamic analysis of grandstands
Máca Jiří; Rokoš Ondřej
2014 - English The purpose of this thesis is to provide a systematic approach to the modelling of the crowd-grandstand problem taking into account various sources of randomness in complex FEM-based numerical approach using geometries, material properties and other parameters from the models for the static analysis. Further, to quantify performance and efficiency of this method in comparison with direct Monte Carlo simulation. To this end, stochastic calculus in terms of Itô's integral and Brownian motion process is employed to derive moment equations describing the resulting output quantities which can be subsequently used to asses overall serviceability and reliability of the system. Utilizing various methods which reduce the size of the corresponding mathematical model, the approach becomes tractable and quite efficient. It is demonstrated on several examples that not only the randomness of the induced active crowd forces can be captured, but also a random spatial distribution of a crowd and uncertainties in biodynamic models reflecting passive spectators. Since the approach is in its essence analytical, it illuminates and reveals several relationships between the behavior of the system response and particular sources of randomness.The purpose of this thesis is to provide a systematic approach to the modelling of the crowd-grandstand problem taking into account various sources of randomness in complex FEM-based numerical approach using geometries, material properties and other parameters from the models for the static analysis. Further, to quantify performance and efficiency of this method in comparison with direct Monte Carlo simulation. To this end, stochastic calculus in terms of Itô's integral and Brownian motion process is employed to derive moment equations describing the resulting output quantities which can be subsequently used to asses overall serviceability and reliability of the system. Utilizing various methods which reduce the size of the corresponding mathematical model, the approach becomes tractable and quite efficient. It is demonstrated on several examples that not only the randomness of the induced active crowd forces can be captured, but also a random spatial distribution of a crowd and uncertainties in biodynamic models reflecting passive spectators. Since the approach is in its essence analytical, it illuminates and reveals several relationships between the behavior of the system response and particular sources of randomness. Keywords: grandstand; active crowd; passive crowd; white noise process; biodynamic model; spatial crowd distribution; dynamic response; serviceability and reliability assessment; simulation; stochastic differential equations. Available at various departments of the ČVUT. Dynamic analysis of grandstands

The purpose of this thesis is to provide a systematic approach to the modelling of the crowd-grandstand problem taking into account various sources of randomness in complex FEM-based numerical ...

Máca Jiří; Rokoš Ondřej
České vysoké učení technické v Praze, 2014

Comparative static analysis of tunnelling methods NATM and ADECO-RS
Barták Jiří; Černá Vydrová Linda; Šejnoha Michal
2014 - English New Austrian Tunnelling Method (NATM) has been used almost exlusively in the Czech Republic in the last three decades. This method has many supporters, whose resistance to new methods and approaches prevents the integration of other methods to the tunnelling industry in the Czech Republic. One of the methods thus neglected is the Italian method called ADECO-RS, which has reached significant use also outside Italy. It is a method of controlled deformation, which uses mainly the horizontal anchoring of the tunnel face to reinforce the area in front of the face (advance core). This technology is especially important in weak and soft rocks where it is necessary to excavate quickly and smoothly with minimum disruption of initial stress state of the rock mass in the vicinity of the excavation. It can be assumed that the use of NATM is in some cases uneconomical and technically inadequately challenging and in such cases it would be appropriate to choose another technology. Given the facts above, in the Czech environment there is no data available for comparison of these methods not only in terms of numerical modelling, but also in terms of feasibility and usability.The work briefly summarizes the history of the tunnelling methods and it is closer devoted to NATM and ADECO-RS tunnelling approaches. The basic principles of both methods are set and further the comparison of these methods is made on a theoretical level and in terms of numerical modelling, which was performed in the program PLAXIS 3D-Tunnel. The thesis hereinafter includes the analysis of fibreglass face anchors application during the construction of three-aisled Veleslavín Station and the impact assessment of tunnel face anchoring during the excavation of ventilation tunnel on the newly built part of the Prague Metro "V.A". The work also deals with practical knowledge gained during the technical visit of Italian Val di Sambro tunnel which is built according to ADECO-RS approach. These findings are essential for the correct interpretation of Lunardi method. Finally, the thesis briefly summarize the tunnel construction process by ADECO-RS method.New Austrian Tunnelling Method (NATM) has been used almost exlusively in the Czech Republic in the last three decades. This method has many supporters, whose resistance to new methods and approaches prevents the integration of other methods to the tunnelling industry in the Czech Republic. One of the methods thus neglected is the Italian method called ADECO-RS, which has reached significant use also outside Italy. It is a method of controlled deformation, which uses mainly the horizontal anchoring of the tunnel face to reinforce the area in front of the face (advance core). This technology is especially important in weak and soft rocks where it is necessary to excavate quickly and smoothly with minimum disruption of initial stress state of the rock mass in the vicinity of the excavation. It can be assumed that the use of NATM is in some cases uneconomical and technically inadequately challenging and in such cases it would be appropriate to choose another technology. Given the facts above, in the Czech environment there is no data available for comparison of these methods not only in terms of numerical modelling, but also in terms of feasibility and usability.The work briefly summarizes the history of the tunnelling methods and it is closer devoted to NATM and ADECO-RS tunnelling approaches. The basic principles of both methods are set and further the comparison of these methods is made on a theoretical level and in terms of numerical modelling, which was performed in the program PLAXIS 3D-Tunnel. The thesis hereinafter includes the analysis of fibreglass face anchors application during the construction of three-aisled Veleslavín Station and the impact assessment of tunnel face anchoring during the excavation of ventilation tunnel on the newly built part of the Prague Metro "V.A". The work also deals with practical knowledge gained during the technical visit of Italian Val di Sambro tunnel which is built according to ADECO-RS approach. These findings are essential for the correct interpretation of Lunardi method. Finally, the thesis briefly summarize the tunnel construction process by ADECO-RS method. Keywords: NATM; ADECO-RS; tunnelling; tunnel face; advance core; numerical modelling; horizontal anchoring Available at various departments of the ČVUT. Comparative static analysis of tunnelling methods NATM and ADECO-RS

New Austrian Tunnelling Method (NATM) has been used almost exlusively in the Czech Republic in the last three decades. This method has many supporters, whose resistance to new methods and approaches ...

Barták Jiří; Černá Vydrová Linda; Šejnoha Michal
České vysoké učení technické v Praze, 2014

Planetary investigation by global numerical simulations:Study of Hermean environment
Trávníček Pavel; Herčík David; Kulhánek Petr
2014 - English Analysis of Mercury´s magnetosphere via hybrid simulationsAnalysis of Mercury´s magnetosphere via hybrid simulations Keywords: Mercury; magnetosphere; solar wind interaction,hybrid numerical simulations Available at various departments of the ČVUT. Planetary investigation by global numerical simulations:Study of Hermean environment

Analysis of Mercury´s magnetosphere via hybrid simulationsAnalysis of Mercury´s magnetosphere via hybrid simulations

Trávníček Pavel; Herčík David; Kulhánek Petr
České vysoké učení technické v Praze, 2014

ANDREA an integrated framework for in-core fuel management analyses
Vočka Radim; Havlůj František; Heřmanský Bedřich
2014 - English Available at various departments of the ČVUT. ANDREA an integrated framework for in-core fuel management analyses

Vočka Radim; Havlůj František; Heřmanský Bedřich
České vysoké učení technické v Praze, 2014