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Design and implementation of device for dynamic loading of laboratory model of rail track based on pre-stressed stiffness
Turza, Šimon ; Lošák, Petr (referee) ; Kšica, Filip (advisor)
This bachelor thesis deals with the design, implementation, and validation of a loading fixture based on the principle of pre-stressed stiffness for a railway track model. The literature review summarizes the available methods for dynamic modeling of railway tracks and describes the laboratory model used. Furthermore, the thesis addresses the design and implementation of the fixture, which was developed based on the requirements arising from the shortcomings of previous solutions. The final part focuses on the experimental validation of the fixture's functionality and its comparison with previous solutions.
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Development of the HSBT tensile impact test equipment
Pech, Vladimír ; Harant, Martin (referee) ; Jopek, Miroslav (advisor)
The thesis is focused on the design of a device for tensile impact tests based on the Hopkinson's split bar principle. The theoretical part describes the behaviour of materials under dynamic loading conditions and a description of the testing methods used. The thesis describes in detail the Hopkinson tensile test and different design variants of this device, including their principle, advantages and disadvantages. In the practical part of the thesis is designed the testing device and the individual parts of the device are analyzed. For the key parts, the selection of materials and geometric parameters is described to ensure the proper functionality of the device. The constructed device is tested by samples made from PETG material. Capacitive sensors and strain gauges were used to record data during the test to verify the correct functionality of the device.
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Mechanical properties of basalt: a study on compressive loading at different strain rates using SHPB
Falta, J. ; Krčmářová, N. ; Fíla, T. ; Vavro, Martin ; Vavro, Leona
This article focuses on the mechanical properties of basalt in compressive loading at different strain-rates. The study employs advanced instrumentation for the evaluation of the results in dynamic conditions, while standard uni-axial loading device is used for evaluation in quasi-static conditions. Basalt specimens were subjected to four different loading-rates from 200–600 s−1 on which the stress-strain dependence was evaluated together with DIC analysis of crack initiation and disintegration process. Understanding the mechanical properties of basalt can provide insights for engineers and designers in creating structures that are durable and able to withstand different loading conditions. The findings of this study can have implications for a wide range of industries, including aerospace, automotive, and construction, among others.
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Ballistic-Proof Concretes
Koutný, Ondřej ; Bílek,, Vlastimil (referee) ; Keršner, Zbyněk (referee) ; Ptáček, Petr (advisor)
Doctoral thesis „Ballistic-proof concretes“ deals with description, design and development of material based on ultra-high performance fibre reinforced cementitious composite with increased ballistic resistance i.e. increased resistance against high-strain rate dynamic loading induced by interaction of high-velocity moving objects. High mechanical properties, essential for such a material, are reached especially by maximal reduction of water-to-binder coefficient using high-range water reducing agents, high-strength aggregates and dense structure by precise selection and dosage of raw materials in the recipe. The main goal is to prepare a methodology for design of such a materials, observation of material behaviour on ballistic loading and quantitative description of material response for protective structures design. Properties of designed materials within this thesis are comparing with properties of commercially available and commonly used cementitious composites in order to create a concept for material limits in the field of ballistic protection. This concept enables to estimate ballistic protection of present or newly-designed materials and structures.
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The use of Electrical Properties of Composites with Modified Cement Matrix
Macháň, Ladislav ; Husák, Miroslav (referee) ; Sýkora, Jiří (referee) ; Šteffan, Pavel (advisor)
The dissertation thesis is focused on practical use of composite material with modified cement matrix. Especially the area of electrical behavior of composite materials in use has been examined, for strain sensing material. The experimental part solves the problematics of corrosion of carbon and metallic materials in alkaline environment of the cement matrix. The physical design of the sensor and its fabrication using functional composite cement material have been described here. The thesis has also discussed defining the influence of temperature change and humidity change on the change of electrical parameters of integrated sensors. An important part of the thesis is the area of evaluating a series of measurements of electrical parameters under dynamic loading. The thesis analyzes designed measurement method in detail, being suitable to determine electrical properties of cement composite materials including the construction of a monitoring system that enables practical application of sensors in complex structures.
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Failure analysis of the space shuttle Columbia
Neduchal, Ondřej ; Man, Ondřej (referee) ; Pantělejev, Libor (advisor)
Bachelor´s thesis is focused on the analysis of the space shuttle Columbia accident. Text firstly generally discusses materials used in aviation and cosmonautic, specifically composite materials. These are discussed firstly in general and then is the thesis focused on their strength and dynamic properties. Second half of the thesis describes the course of the last flight of the space shuttle Columbia and its subsequent demise. Emphasis is placed on the cause of the accident in which plays a crucial influence the material on the surface of the wing.
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New Findings in Calculating of the Subgrade Response on High-Speed Lines to Train Passage
Petýrek, Michal ; Horníček, Leoš
The article presents the possibilities of approaches to the calculation of the subsoil response of a railway line to high-speed train running with a focus on Rayleigh waves. The article describes in more detail the approach to the calculation using the method of thin layers, which seems promising for the calculation of the response of the track with the construction of the track with transverse sleepers. The article is focused on this method with regard to the expected use of the track with sleepers on high-speed lines in the Czech Republic. Furthermore, the article mentions the implementation of nonlinear behaviour of soil under dynamic load during the passage of the train and the issue of calculating the subsoil of the line formed by multiple layers of soil with different parameters.
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Ballistic-Proof Concretes
Koutný, Ondřej ; Bílek,, Vlastimil (referee) ; Keršner, Zbyněk (referee) ; Ptáček, Petr (advisor)
Doctoral thesis „Ballistic-proof concretes“ deals with description, design and development of material based on ultra-high performance fibre reinforced cementitious composite with increased ballistic resistance i.e. increased resistance against high-strain rate dynamic loading induced by interaction of high-velocity moving objects. High mechanical properties, essential for such a material, are reached especially by maximal reduction of water-to-binder coefficient using high-range water reducing agents, high-strength aggregates and dense structure by precise selection and dosage of raw materials in the recipe. The main goal is to prepare a methodology for design of such a materials, observation of material behaviour on ballistic loading and quantitative description of material response for protective structures design. Properties of designed materials within this thesis are comparing with properties of commercially available and commonly used cementitious composites in order to create a concept for material limits in the field of ballistic protection. This concept enables to estimate ballistic protection of present or newly-designed materials and structures.
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The use of Electrical Properties of Composites with Modified Cement Matrix
Macháň, Ladislav ; Husák, Miroslav (referee) ; Sýkora, Jiří (referee) ; Šteffan, Pavel (advisor)
The dissertation thesis is focused on practical use of composite material with modified cement matrix. Especially the area of electrical behavior of composite materials in use has been examined, for strain sensing material. The experimental part solves the problematics of corrosion of carbon and metallic materials in alkaline environment of the cement matrix. The physical design of the sensor and its fabrication using functional composite cement material have been described here. The thesis has also discussed defining the influence of temperature change and humidity change on the change of electrical parameters of integrated sensors. An important part of the thesis is the area of evaluating a series of measurements of electrical parameters under dynamic loading. The thesis analyzes designed measurement method in detail, being suitable to determine electrical properties of cement composite materials including the construction of a monitoring system that enables practical application of sensors in complex structures.
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Failure analysis of the space shuttle Columbia
Neduchal, Ondřej ; Man, Ondřej (referee) ; Pantělejev, Libor (advisor)
Bachelor´s thesis is focused on the analysis of the space shuttle Columbia accident. Text firstly generally discusses materials used in aviation and cosmonautic, specifically composite materials. These are discussed firstly in general and then is the thesis focused on their strength and dynamic properties. Second half of the thesis describes the course of the last flight of the space shuttle Columbia and its subsequent demise. Emphasis is placed on the cause of the accident in which plays a crucial influence the material on the surface of the wing.
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