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New Aluminium Alloys in Aircraft Structures
Przeczek, Jan ; Šplíchal, Jan (referee) ; Klement, Josef (advisor)
This bachelor work deals with newly developed wrought aluminium alloys, designed for application in aerospace industry. The task of that work is to compare recent aircraft aluminium alloys with conventional alloys and indicate direction of progress in this field. The comparison is particularly focused on improvement of mechanical and/or technological properties of these alloys.
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Diagnostic methods for the evaluation of the state of timber structures
Štěpánek, Jakub ; Stehlík, Michal (referee) ; Heřmánková, Věra (advisor)
This thesis is dealing with diagnostic methods and methodics of research of timber constructions. Theoretical part is focusing on timber as material for constructions, it's defects, physical and mechanical properties, overview of diagnostic methods and their appropriateness of use. In practical part I am describing performed diagnosis of element of timber construction with focusing on comparing transfer speed of the ultrasonic waves to selected mechanical and physical properties.
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Titanium oxide and its properties in building materials
Rypák, Peter ; Vyšvařil, Martin (referee) ; Rovnaník, Pavel (advisor)
Theoretical part of thesis deals with conclusion of aquired informations about photocatalysis of titanium dioxide, its influence on properties of chosen building materials and its practic use in research of building materials with abitlity to decompose organic and anorganic matters. Experimental part deals with influence of quantity of titanium dioxide on mechanical strength of tested samples based on alkali activated slag and its ability to decompose organic colorant Rhodamine B
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Artificial stone - methods of preparation and properties
Pluskalová, Barbora ; Bayer, Patrik (referee) ; Rovnaník, Pavel (advisor)
The aim of the thesis „Artificial stone – Methods of preparation and it´s properties“ deals with the various methods and issues concerning the preparation of artificial stone. The thesis presents the summary of materials and various methods suitable for the preparation and points out mechanical properties, including durability of material, which serves as an alternative to natural stone. Further on, the thesis deals with the studies of binding systems based on geopolymers, which are used for the artificial stone preparation. This part of the thesis is associated with the experimental part, which is aimed at choosing the suitable mixing ratio of binder to aggregate in the artificial stone based on metakaolin geopolymer. According to the results of mechanical tests and aesthetic impression the author chose the best composition and then created a decorative element.
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Measuring strength and modulus of deformability of wood in compression parallel to the grain in a bored hole by a small jack\n
Kloiber, Michal
The publication is dedicated to the methodical description of the technical solution and the measurement of strength and modulus of deformability of wood in compression parallel to the grain in a bored hole by pushing apart grips of a small jack and loading the walls of the hole. The methodology presents the principles of the device usage and measurement result evaluation for the purposes of surveys of historical monuments and projects for their rescue or appreciation. Currently, there is no other method allowing determination of mechanical properties of wood, such as strength and modulus of elasticity in compression parallel to the grain, directly in the field without sampling. Therefore, the research was oriented to the development of a simple method, practically applicable for the purpose of structural-technical surveys of timber structures, in particular historical monuments. The resulting methodology meets the protection of the cultural heritage standards, in particular the requirement to minimize interference with the original material, while retaining high reliability of the determined wood mechanical properties of wood.
Fulltext: content.csg -  PDF
Plný tet: 0453514_2015_Kloiber_Mereni_pevnosti_a_modulu_pretvarnosti_dreva_CM_NAKI-001 - PDF
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Properties of commercially available, ready-to-use mortars for restoration of historic renders and masonry
Janotová, Dana ; Niedoba, Krzysztof ; Gláser, Petr ; Šašek, Petr ; Fabeš, Roman
There is a wide range of premixed, dry mortars, on the market, designed with the reconstruction of historic renders and masonry in mind. The use of such materials has some advantages, including good workability and standard quality, however, due to unknown composition, being a secret of a manufacturer, it is frequently impossible to predict their influence on the substrate and on the ageing. If the ready-to-use mortar is to be applied during the renovation of the historic masonry, it is necessary to know: how close the mortars’ properties match the properties of the original material; will the repair be durable enough and will it degrade faster than the original material. Technical information, provided by the manufacturer, does not contain such data. The only parameters given, are the strength, porosity of hardened mortar and water vapour diffusion coefficient, however, it is not specified in which conditions these values were measured.
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THE EFFECT OF MO AND/OR C ADDITION ON MICROSTRUCTURE AND PROPERTIES OF TIAL ALLOYS
Chlupová, Alice ; Kruml, Tomáš ; Roupcová, Pavla ; Heczko, Milan ; Obrtlík, Karel ; Beran, Přemysl
Cast TiAl alloys with high Nb content are subject of extensive research with the aim to develop material with low density, good corrosion resistance and high strength at elevated temperatures. Disadvantage of their broad applications is restricted workability, machinability and low fracture toughness especially at room temperature. Improvement of properties of TiAl based materials can be achieved by tailoring the microstructure by modification of chemical composition. For this purpose 5 types of TiAl alloys with 7 % of Nb were prepared having variable content of Mo and/or C. Addition of Mo and/or C resulted in three types of microstructure and different phase composition. All modified alloys contain colonies consisting of thin lamellae of a and g phases sometimes complemented by g and/or b phase at the grain boundaries. Variable microstructure and phase composition resulted in differences in mechanical behaviour. The most promising tensile properties at both room and elevated temperature were observed for alloy doped with 2 % of Mo having the mixed microstructure containing b phase and for alloy doped with 0.5 % of C with nearly lamellar microstructure without b phase. 2Mo alloy exhibited reasonably good ductility while 0.5C alloy reached the highest tensile strength. Also low cycle fatigue behaviour of these two materials was the best of all five materials under investigation. Fatigue deformation characteristics were better in the case of 2Mo alloy while 0.5C alloy exhibited higher cyclic stresses. Fracture mechanisms were determined using fractographic analysis. The major fracture mode of all alloys was trans-lamellar.
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A Comparison of Different Measurement Method of Mechanical Properties of Al Thin Film
Truhlář, M. ; Buršíková, V. ; Sobota, Jaroslav ; Kruml, Tomáš
The paper compares two different methods for testing of metallic thin films: microcompression test and nanoindentation. Microcompression test is one possibility how to perform mechanical tests on a very small scale. This method requires preparation of a small cylindrical specimen (micropillar) of micrometric size by FIB and execution of a compression test using nanoindenter device equipped with a flat diamond punch. Stressstrain curves of the thin films were obtained from such tests. Nanoindentation tests were then conducted to compare the results on the same films. Two different metal thin films – AlCuW, AlCuSi with thickness 2 .mu.m and grain size 3.8 .mu.m in average were prepared by PVD method. In this paper, we announce the results of measurements, a comparison of the results obtained by each method and identify advantages and limitations of the methods.
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