|
|
Residual fatigue life estimation of railway wheelset
Pokorný, Pavel ; Zouhar, Michal (referee) ; Náhlík, Luboš (advisor)
The first part of this master's thesis deals with the high cycle fatigue of materials, especially on growing cracks using linear elastic fracture mechanics. Much of this work is focused on the concept of stress intensity factor. This concept is nowadays one of the most widely used concepts for describing a body with crack. The first part ends with theoretical approaches to determine the residual fatigue life of the body with a crack. The second part of this master's thesis is focused on the determination of residual fatigue life of a specified railway wheelset. An existence of crack-like defect is assumed at the railway wheelset. The goal of this master's thesis is to estimate how long it will take to grow from initial defect to a critical crack length. The last part of this master's thesis is devoted to addiction order load cycles on crack growth rate.
|
|
|
Methodology of Passportization of Building Objects Damaged by Surrounding Activities
Novák, Jindřich ; Hobst, Leonard (referee) ; Anton, Ondřej (advisor)
The passportization of building structures is very important task efore the initiation of negative influences on to object. The aim is to prevent possible legal deputies in between owners of affected object. The demand of passportization of building structure is increasing with the exploding of developments projects from green fields to vacancies. The aim of this work is to determine the metodology of passportization of building structures and to apply it on existig object.
|
|
|
A study of the stress field near the stress concentrator at the bi-material interface
Krepl, Ondřej ; Klusák, Jan (referee) ; Profant, Tomáš (advisor)
The aim of this work is the solution of problems of the stress distribution near bimaterial notch tip or eventually the crack impinging orthogonaly the bimaterial interface, determination of stress singularity exponent. The first part is concerned with basics of linear elastic fracture mechanics, i.e. Irwin's concept of stress intensity factor. The second part is devoted to description of anisotropic materials by complex potencial theory. The final part is focused on calculation of eigenvalues of both isotropic and anisotropic materials and application of LES formalism on the calculation of stress singularities of the bimaterial ortotropic notch or the crack impinging orthogonaly the bimaterial interface.
|
|
|
Evaluation of fracture test of selected core-drilled cylindrical specimen
Halfar, Petr ; Sobek, Jakub (referee) ; Keršner, Zbyněk (advisor)
The diploma thesis deals with effective crack model for a cylinder specimen with an chevron-shaped notch, loaded by a three-point bending. The first part of the thesis is theoretical and the it describes the use of fracture mechanics for quasi-brittle materials – concrete and rocks. Furthermore there is described the linear elastic fracture mechanics and founding the geometry function for a different geometries of fracture tests. The second part describes the FEM program, which was used to calculate the fracture parameters, that were used to determine the length of the effective crack and how the program was tested before it was used. The last part describe calculations of fracture toughness by using the effective crack model on selected rock and concrete specimens.
|
|
|
Fracture Toughness of Metallic Materials and its Testing
Kosek, Lukáš ; Zapletal, Josef (referee) ; Němec, Karel (advisor)
The purpose of the work is to introduce the basic of the fracture toughness of metallic materials and its measuring under the conditions of the plane strain. There are shown essential concepts of the linear elastic fracture mechanics, which is used for the description of the material behavior at fracture of the material with a crack. It defines stress intensity factor and describes the main elements influencing the fracture toughness. Furthermore, the work contains the particular testing methods, specimens and testing equipments. In the conclusion it recapitulates the availability and the application of the linear elastic fracture mechanics.
|
|
| |
|
| |
|
|
An aplication of the mathematical dislocation theory to the problem of the crack in the vicinity of the bi-material interface
Padělek, Petr ; Hrstka, Miroslav (referee) ; Profant, Tomáš (advisor)
The presented diploma thesis deals with a problem of the determination of the stress intensity factor of the finite length crack in the vicinity of the bi-material interface solved by the distributed dislocation technique. The work is divided into several parts. The first part is theoretical and includes basic concepts of the fracture mechanics, the crack behaviour at the bi-material interface, the formulation of the singular integral equation by virtue of the distributed dislocation technique, the Bueckner's principle, complex potentials and consequently the determination of the stress intensity factor. The second part is the theory application to the specific configuration of the crack of the finite length with respect to the bi-material interface and in the third part, there is carried out the solution of this problem for various configurations of the bi-material solved by the distributed dislocation technique and its comparison with the results obtained from the FE analysis.
|
|
|
Crack in prismatic bars
Meňhert, Samuel ; Hrstka, Miroslav (referee) ; Profant, Tomáš (advisor)
This thesis deals with summarization of information about fracture mechanics mainly with methods which estimate stress intensity factors. They play an important role in determination of behavior of cracks in engineering process. The main goal of this thesis will be familiarization with Kienzler hypothesis which deals with strain energy release rate and internal effects in a point of disrupted cross section and comparison with classic K-concept, when the stress intensity factors are determined by infinite series.
|
|
|
Reduction prices house in Lelekovice as a result of defects or faults.
Faltusová, Veronika ; Uhlová, Eva (referee) ; Weigel, Lubomír (advisor)
This thesis deals with the issue of determining the causes of defects and failures, focusing on a specific property and their significance in determining the price of the property. The first part focuses on the theory explaining the basic concepts used in the valuation of real estate, basic methods of property valuation and classification of construction defects and failures. This chapter includes an analysis of the real estate market in the years 2008 - 2013. The second part is devoted to determining the amount of property damage at a specific property, the calculation of this particular property which is based on technical surveys and subsequent valuation of the property with regard to the results of the survey. The aim is to create a design procedure for reducing the price of the property with the defect.
|
guest ::
